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National Instruments Drums 320685D-01 User's Manual

1. 3 6 Bit Fields 3 6 Returning Floats and Doubles 3 7 Returning Structures 3 7 Enum Sizes 3 7 Long Doubles 3 7 Differences between LabWindows CVI and the External Compilers 3 7 External Compiler Versions Supported 3 8 Required Preprocessor Definitions 3 8 Multithreading and the LabWindows CVI Libraries 3 8 Using LabWindows CVI Libraries in External Compilers 3 9 Include Files for the ANSI C Library and the LabWindows CVI Libraries 3 10 Standard Input Output Window 3 10 Resolving Callback References from UIR Files 3 10 Linking to Callback Functions Not Exported f
2. 6 3 Chapter 7 Creating and Distributing Standalone Executables and DLLs Introduction to the Run Time Engine 7 1 Distributing Standalone Executables under Windows 7 1 Minimum System Requirements for Windows 95 NT 7 1 No Math Coprocessor Required for Windows 95 NT 7 2 Minimum System Requirements for Windows 3 1 7 2 Math Coprocessor Software Emulation for Windows 3 1 7 2 Distributing Standalone Executables under UNIX 7 2 Distributing Standalone Executables under Solaris 2 7 3 Distributing Standalone Executables under Solaris 1 7 4 Minimum System Requirements for UNIX 7 5 Translating the Message File 7 5 Configuring the Run Time Engine 7 5 Solaris 1 Patches Required for Running Standalone Executable 7 5 Configuration Option Descriptions 7 6 cvirtx Windows 3 1 Only 7 6 cvid
3. 9 5 TCP Library 9 6 DDE Library 9 6 00ProRef book 00ProRefTOC fm Page xi Monday March 9 1998 3 23 PM Contents LabWindows CVI Programmer Reference Manual xii National Instruments Corporation ActiveX Automation Library 9 6 X Property Library 9 6 Formatting and I O Library 9 6 Utility Library 9 7 ANSI C Library 9 7 LabWindows CVI Instrument Drivers 9 7 Appendix A Errors and Warnings Appendix B Customer Communication Glossary Figures Figure 7 1 Files Necessary to Run a LabWindows CVI Executable Program on a Target Machine 7 8 Tables Table 1 1 LabWindows CVI Compiler Limits
4. 3 27 Setting Up Include Paths for LabWindows CVI ANSI C and SDK Libraries 3 28 Compiling in LabWindows CVI for Linking in LabWindows CVI 3 28 Compiling in LabWindows CVI for Linking in an External Compiler 3 28 Compiling in an External Compiler for Linking in an External Compiler 3 28 Compiling in an External Compiler for Linking in LabWindows CVI 3 29 Handling Hardware Interrupts under Windows 95 NT 3 29 Chapter 4 Windows 3 1 Compiler Linker Issues Using Modules Compiled by LabWindows CVI 4 1 Using 32 Bit Watcom Compiled Modules under Windows 3 1 4 1 Using 32 Bit Borland or Symantec Compiled Modules under Windows 3 1 4 2 16 Bit Windows DLLs 4 3 Helpful LabWindows CVI Options for Working with DLLs 4 4 DLL Rules and Restrictions 4 4 00ProRef book 00ProRefTOC fm Page viii Monday March 9 1998 3 23 PM Contents National Instruments Corporation ix LabWindows CVI Programmer Reference Manual DLL Glue Code
5. 5 6 Locking Process Segments into Memory Using plock 5 7 UNIX Asynchronous Signal Handling 5 7 00ProRef book 00ProRefTOC fm Page ix Monday March 9 1998 3 23 PM Contents LabWindows CVI Programmer Reference Manual x National Instruments Corporation Solaris 1 ANSI C Library Implementation 5 8 Replacement Functions 5 9 Additional Functions Not Found in Sun Solaris 1 libc 5 9 Incompatibilities among LabWindows CVI Sun Solaris and ANSI C 5 10 Between LabWindows CVI and ANSI C 5 10 Between LabWindows CVI and Sun Solaris 5 11 Chapter 6 Building Multiplatform Applications Multiplatform Programming Guidelines 6 1 Library Issues 6 1 Externally Compiled Modules 6 3 Multiplatform User Interface Guidelines
6. 2 1 Advantages and Disadvantages of Using Loadable Compiled Modules in LabWindows CVI 2 2 Using a Loadable Compiled Module as an Instrument Driver Program File 2 2 Using a Loadable Compiled Module as a User Library 2 3 Using a Loadable Compiled Module in the Project List 2 3 Using a Loadable Compiled Module as an External Module 2 4 Notification of Changes in Run State 2 4 Example 1 2 5 Example 2 2 6 Using Run State Change Callbacks in a DLL 2 6 Compiled Modules that Contain Asynchronous Callbacks 2 7 Chapter 3 Windows 95 NT Compiler Linker Issues Loading 32 Bit DLLs under Windows 95 NT 3 1 DLLs for Instrument Drivers and User Libraries 3 2 Using The LoadExternalModule Function
7. 4 7 DLLs That Can Use Glue Code Generated at Load Time 4 8 DLLs That Cannot Use Glue Code Generated at Load Time 4 8 Loading a DLL That Cannot Use Glue Code Generated at Load Time 4 8 Rules for the DLL Include File Used to Generate Glue Source 4 9 If the DLL Requires a Support Module outside the DLL 4 9 If You Pass Arrays Bigger Than 64 K to the DLL 4 9 If the DLL Retains a Buffer after the Function Returns an Asynchronous Operation 4 11 If the DLL Calls Directly Back into 32 Bit Code 4 12 If the DLL Returns Pointers 4 15 If a DLL Receives a Pointer that Points to Other Pointers 4 18 DLL Exports Functions by Ordinal Value Only 4 20 Recognizing Windows Messages Passed from a DLL 4 21 Creating 16 bit DLLs with Microsoft Visual C 1 5 4 21 Creating 16 bit DLLs with Borland C 4 22 DLL Search Precedence 4 23 Chapter 5 UNIX Compiler Linker Issu
8. 3 2 Link Errors when Using DLL Import Libraries 3 2 DLL Path pth Files Not Supported 3 2 16 Bit DLLs Not Supported 3 2 00ProRef book 00ProRefTOC fm Page vi Monday March 9 1998 3 23 PM Contents National Instruments Corporation vii LabWindows CVI Programmer Reference Manual Run State Change Callbacks in DLLs 3 2 DllMain 3 3 Releasing Resources when a DLL Unloads 3 3 Generating an Import Library 3 4 Default Unloading Reloading Policy 3 4 Compatibility with External Compilers 3 4 Choosing Your Compatible Compiler 3 5 Object Files Library Files and DLL Import Libraries 3 5 Compatibility Issues in DLLs 3 5 Structure Packing
9. Set the include directories to point to cvi include before other include directories Turn off the Allocate Enums as Ints option Turn off the Fast Floating Point option Use the C calling convention If you use a file with a c extension Borland C 4 x compiles it as a C source file If your file has a cpp extension Borland C 4 x compiles it as a C source file you must use extern C for any functions or variables you want to access from a C file Use the following options when you compile with Symantec C 6 0 Set the target to be a Win32s executable Define _NI_mswin16_ Set the include directories to point to cvi include before any other include directories Set Structure Alignment to 1 byte Turn off the Use Pascal Calling Convention option 16 Bit Windows DLLs You can call functions in a 16 bit DLL from source code or from a 32 bit compiled module You can compile your 16 bit DLL in any language using any compiler that generates DLLs If you want to program with DMA or interrupts or access the Windows API you must use a Windows DLL 00ProRef book 06chap04 fm Page 3 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 4 National Instruments Corporation You must observe certain rules and restrictions in a DLL you want to use with LabWindows CVI If you experience problems using a DLL in L
10. 1 1 Table 1 2 LabWindows CVI Allowable Data Types 1 6 Table 1 3 Stack Size Ranges for LabWindows CVI 1 16 Table 7 1 LabWindows CVI Run Time Engine Files 7 10 Table 7 2 Windows NT Registry Entry Values for the Low Level Support Driver 7 11 Table 7 3 Pathnames and Targets of Links 7 12 Table A 1 Error Messages A 1 00ProRef book 00ProRefTOC fm Page xii Monday March 9 1998 3 23 PM National Instruments Corporation xiii LabWindows CVI Programmer Reference Manual About This Manual The LabWindows CVI Programmer Reference Manual contains information to help you develop programs in LabWindows CVI The LabWindows CVI Programmer Reference Manual is intended for use by LabWindows users who have already completed the Getting Started with LabWindows CVI tutorial To use this manual effectively you should be familiar with Getting Started with LabWindows CVI the LabWindows CVI User Manual DOS Windows and the C programming language Organization of This Manual The LabWindows CVI Programmer Reference Manual is organized as follows Chapter 1 LabWindows CV
11. 5 To run your executable you must have the LabWindows CVI Run time Engine You can build the package for the LabWindows CVI Run time Engine by executing makecvirte located in the misc bin directory of the LabWindows CVI installation directory The 00ProRef book 06chap07 fm Page 3 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 4 National Instruments Corporation makecvirte script prompts you to name the directory in which to place the completed package The package name is NICcvirte 6 To install or remove a package on a machine you must log in as root You can then use either of the following two methods to install or remove a package Use the Software Management Tool swntool located in the usr sbin directory of your system Use the following command to install a package pkgadd d lt path to package gt pkgname To remove a previously installed package issue the following command pkgrm pkgname Distributing Standalone Executables under Solaris 1 To distribute executable programs under Solaris 1 complete the following steps 1 If your program loads UIR files with LoadPanel or loads external modules with LoadExternalModule use caution when you specify filenames in calls to these functions If you use a relative path the path is relative to the directory that contains the executable Refer to the Locatio
12. Compile Error Preprocessor conditional directive ifndef requires an identifier following it on the same line Make sure that an identifier follows ifndef on the same line line directive cannot specify line 0 Compile Error line preprocessor directive requires a non zero line number value line directive cannot specify line greater than 32767 Compile Error line preprocessor directive cannot set the line greater than 32 767 line directive expects numeric argument Compile Error line preprocessor directive requires a line number value to be specified following line at beginning of macro definition Compile Error preprocessing token is at the beginning of a macro definition Ensure that a preprocessing token precedes 00ProRef book 07AppA fm Page 1 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 2 National Instruments Corporation at end of macro definition Compile Error preprocessing token is at the end of a macro definition Ensure that a preprocessing token s follows or expected Compile Error Ensure that the function macro argument list terminates with a and that a separates all the macro arguments 0 flag is not valid with c s p and n modifiers Non Fatal Run time Error Use of an incorrect format specifier or use of a field width starting with 0 might cause thi
13. B Customer Communication For your convenience this appendix contains forms to help you gather the information necessary to help us solve your technical problems and a form you can use to comment on the product documentation When you contact us we need the information on the Technical Support Form and the configuration form if your manual contains one about your system configuration to answer your questions as quickly as possible National Instruments has technical assistance through electronic fax and telephone systems to quickly provide the information you need Our electronic services include a bulletin board service an FTP site a fax on demand system and e mail support If you have a hardware or software problem first try the electronic support systems If the information available on these systems does not answer your questions we offer fax and telephone support through our technical support centers which are staffed by applications engineers Electronic Services Bulletin Board Support National Instruments has BBS and FTP sites dedicated for 24 hour support with a collection of files and documents to answer most common customer questions From these sites you can also download the latest instrument drivers updates and example programs For recorded instructions on how to use the bulletin board and FTP services and for BBS automated information call 512 795 6990 You can access these services at United States 512 794 5
14. For Windows 3 1 the LabWindows CVI Run time Engine comes in the form of an executable file The name of the executable file is cvirtn exe where n is the version of the Run time Engine The Run time Engine comes on a separate diskette The LabWindows CVI installation program installs the Run time Engine along with the development environment The Create Distribution Kit command in the Build menu of the Project window can bundle Table 7 2 Windows NT Registry Entry Values for the Low Level Support Driver Type Name Value DWORD ErrorControl 00000001 String Group Extended Base DWORD Start 00000002 DWORD Type 00000001 00ProRef book 06chap07 fm Page 11 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 12 National Instruments Corporation the Run time Engine into your distribution kit Also you can make copies of this diskette for separate distribution The user selects the directory into which to install the Run time Engine The LabWindows CVI Run time Engine does not include the DLLs or drivers for National Instruments hardware Users can install the DLLs or drivers for their hardware from the distribution disks that National Instruments supplies LabWindows CVI Run Time Engine under Sun Solaris Under Sun Solaris the Run time Engine comes in the form of a shared library called libcvi so n where n is the version numbe
15. Maximum nesting of if ifdef 16 Maximum number of macro parameters 32 Maximum number of function parameters 64 Maximum nesting of compound blocks 32 Maximum size of array struct types 2 31 00ProRef book 06chap01 fm Page 1 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 2 National Instruments Corporation Compiler Options You can set the LabWindows CVI compiler options by selecting Options Compiler Options in the Project window This command opens a dialog box that allows you to set LabWindows CVI compiler options For a discussion of these options refer to the Compiler Options section in Chapter 3 Project Window of the LabWindows CVI User Manual Compiler Defines The LabWindows CVI compiler accepts compiler defines through the Compiler Defines command in the Options menu of the Project window For more information refer to the Compiler Defines section in Chapter 3 Project Window of the LabWindows CVI User Manual C Language Non Conformance LabWindows CVI for UNIX does not allow you to pass a struct as one of a series of unspecified variable arguments Because of this va_arg ap type is not legal in LabWindows CVI if type is a struct type LabWindows CVI accepts the line preprocessor directive but ignores it C Language Extensions The LabWindows CVI compiler has several extensions to the C language The purpose is to make the LabW
16. Compile Error or Warning In an expression the compiler expects the name of a function or pointer to function to precede a In a pragma line the compiler expects the name of a function after the pragma type Function definitions are not allowed in the interactive window Compile Error Function definitions cannot appear in the Interactive Execution window Function FUNCTION STRING NUMBER Non Fatal Run time Error Library function could not perform its task The integer NUMBER is either the function return value or the value of a global variable that explains why the function failed Refer to the library function reference material for more information about the error Function FUNCTION has an unsupported return type size Glue Code Generation Error Glue code generation or the DLL loading facilities do not support the return type of the function Function requires extra code to handle Callbacks FUNCTION Glue Code Generation Error Automatic glue code generation facility cannot generate complete code for this function because one of its parameters is a function pointer or it returns a function pointer You must generate and modify the glue source code h modifier is only valid with d i n o u and x specifiers Non Fatal Run time Error You can only use the h modifier with integer format specifiers Header name literal too long Compile Error Header name length exceeds
17. You must not use the following option to override the default settings Symantec C C You must use the following options to override the default settings You must not use the following options to override the default settings Note Certain specialized options can generate symbol references that cause link errors in LabWindows CVI If you encounter a link error on a symbol in a module you compiled in an external compiler and you do not recognize the symbol try changing your external compiler options ei Force Enums to Type Int bt nt Target Platform is Windows 95 NT mf Flat Memory Model 4s 80486 Stack Based Calling s Disable Stack Depth Checking j Change Char Default to Signed fpi87 Generate In Line 80x87 Code Zp Structure Alignment mn Windows 95 NT Memory Model f Generate In Line 80x87 Code a Struct Alignment P Use Pascal Calling Convention s Check Stack Overflow 00ProRef book 06chap03 fm Page 19 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 20 National Instruments Corporation Creating Executables in LabWindows CVI You can create true 32 bit Windows executables in LabWindows CVI for Windows 95 NT In LabWindows CVI for Windows 3 1 you run standalone programs using a special executable file that contains the LabWindows CVI run time libraries If you run more than one
18. Adding Libraries to User s Library Menu 8 1 Specifying Library Dependencies 8 2 Chapter 9 Checking for Errors in LabWindows CVI Error Checking 9 2 Status Reporting by LabWindows CVI Libraries and Instrument Drivers 9 3 User Interface Library 9 3 Analysis Advanced Analysis Libraries 9 3 Easy I O for DAQ Library 9 4 Data Acquisition Library 9 4 VXI Library 9 4 GPIB GPIB 488 2 Library 9 4 RS 232 Library 9 5 VISA Library 9 5 IVI Library
19. Assume the DLL has the following function char f void char ptr ptr malloc 100 sprintf ptr hello return ptr 00ProRef book 06chap04 fm Page 16 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 17 LabWindows CVI Programmer Reference Manual Then assume that a program in LabWindows CVI uses the function f as follows char bufptr bufptr f printf s bufptr You would have to modify the glue code as shown here char f char ptr char retval unsigned short cw387 char ptr tmpPtr _far farPtr32 _far tmpFarPtr32 int i cw387 Get387CW retval char InvokeIndirectFunction __static_f ptr Set387CW cw387 convert the 16 bit far pointer to a 32 bit far pointer farPtr32 MK_FP32 retval tmpFarPtr32 farPtr32 Calculate the length of the string Cannot call strlen because it does not accept far pointers i 0 while tmpFarPtr32 i Allocate buffer from CVI memory and copy in data if ptr malloc i 1 NULL tmpFarPtr32 farPtr32 tmpPtr ptr while tmpPtr tmpFarPtr32 return ptr 00ProRef book 06chap04 fm Page 17 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 18 National Instruments Corporation If a DLL Receives a Pointer that Points to Other Pointers
20. Run time Error Number was too large to store in the integer of the specified size Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 31 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 32 National Instruments Corporation Pack pragma valid values are 1 2 4 8 and 16 Compile Error pack pragma alignment value parameter must be 1 2 4 8 or 16 Parameter type incompatible with format specifier Non Fatal Run time Error Parameter type is not compatible with the type that the format string expects An argument is either missing or of the wrong type Parameter type mismatch expecting TYPE but found TYPE Non Fatal Run time Error Parameter type does not match the type that the format string expects The arguments might not be in the right order or an argument might be missing Pointer arithmetic involving invalid pointer Non Fatal Run time Error Pointer arithmetic expression is invalid because one of the subexpressions contains an invalid pointer Pointer arithmetic involving null pointer Non Fatal Run time Error Pointer arithmetic expression is invalid because one of the subexpressions contains the value NULL Pointer arithmetic involving pointer to freed memory Non Fatal Run time Error Pointer arithmetic expression is invalid because one of the subexpress
21. __declspec dllimport qualifier 1 3 _export qualifier 1 3 __export qualifier 1 3 3 22 _import qualifier 1 3 __import qualifier 1 3 _NI_mswin_ macro 6 1 _NI_mswin16_ macro 6 1 _NI_mswin32_ macro 6 1 _NI_sparc_ macro 6 1 _NI_unix_ macro 6 1 _stdcall calling convention qualifier 1 2 __stdcall calling convention qualifier creating static libraries note 3 25 creating static objects note 3 26 declaring functions for export 3 21 to 3 22 purpose and use 1 3 16 bit source code converting to 32 bit source code 1 6 to 1 7 16 bit Windows DLLs See Windows 16 bit DLLs 32 bit Borland or Symantec compiled modules under Windows 4 2 to 4 3 32 bit source code converting 16 bit source code to 32 bit source code 1 6 to 1 7 DLL calling directly back into 32 bit code 4 12 to 4 15 32 bit Watcom compiled modules under Windows 3 1 4 1 to 4 2 32 bit Windows DLLs See Windows 32 bit DLLs A a files using with standalone executables 7 9 ActiveX Automation Library 9 6 Add Files to DLL button 7 15 Add Files to Executable button 7 15 Advanced Analysis Library 9 3 Analysis Library 9 3 ANSI C Library include files for Windows 95 NT 3 10 status reporting by 9 7 Sun Solaris libraries incompatibilities with LabWindows CVI 5 10 to 5 11 non ANSI behavior 5 4 Solaris 1 implementation 5 8 to 5 9 static and shared versions 5 3 ANSI C specifications multiplatform application portability 6 2 non ANSI LabWindows CVI compil
22. end of string Non Fatal Run time Error Source string is not large enough to satisfy the destination specifiers Attempt to realloc invalid pointer expression Fatal Run time Error Pointer value you passed to the realloc function is invalid It is probably the result of a previous invalid pointer operation Attempt to realloc pointer to freed memory Fatal Run time Error Pointer value you passed to the realloc function refers to a location in dynamic memory that you already deallocated Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 5 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 6 National Instruments Corporation Attempt to realloc uninitialized pointer Fatal Run time Error Pointer value you passed to the realloc function is invalid because you did not initialize it It is probably an uninitialized local variable You must initialize local variables before you use them Attempt to write beyond end of array Non Fatal Run time Error Output array is smaller than the given format specifiers and input parameters require Attempt to write beyond end of string Non Fatal Run time Error Output string is smaller than the given format specifiers and input parameters require b modifier must precede o modifier Non Fatal Run time Error If both the b and o modifi
23. for example int __declspec dllexport x int __declspec dllimport x 0 Use of keyword __declspec dllexport contradicts previous use of keyword __declspec dllimport at POSITION Compile Error Use of a keyword in a variable definition contradicts a previous definition for example int __declspec dllimport x int __declspec dllexport x 0 Value parameter expected Non Fatal Run time Error You passed a pointer for a format specifier that requires a scalar value Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 45 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 46 National Instruments Corporation Variables defined as DLL imports cannot be defined with an initial value Compile Error You assigned an initial value to a variable defined as a DLL import for example int __import i 0 You must initialize the variable in a separate assignment statement VXI address must be a multiple of 2 for word transfer Fatal Run time Error You attempted to perform VXI word transfer beginning at an odd address VXI address must be a multiple of 4 for longword transfer Fatal Run time Error You attempted to perform a VXI longword transfer beginning at an address that is not a multiple of 4 w modifier not valid with l format specifier Non Fatal Run time Error You
24. if you do not call InitCVIRTE your executable cannot work For this reason 00ProRef book 06chap05 fm Page 4 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues National Instruments Corporation 5 5 LabWindows CVI Programmer Reference Manual National Instruments recommends that you always include source code similar to the following example in your program int main int argc char argv if InitCVIRTE 0 argv 0 0 return 1 Failed to initialize your program code here If you pass NULL for the second argument to InitCVIRTE your program might still work but with the following limitations Your executable cannot accept the display command line argument As a result you cannot specify an X display on the command line for your program to use You still can use the DISPLAY environment variable to specify a different X display LoadPanel LoadExternalModule DisplayImageFile SavePanelState RecallPanelState and other functions that normally use the directory of the executable to search for files use the current working directory instead If you run the executable from a directory other than the one that contains your executable some of these functions might fail to find files Run State Change Callbacks Are Not Available in Executables When you use a compiled module in LabWindows CVI you can arrange for LabWindows CVI to notify it of a change in execution status start
25. signed unsigned lt struct or union specifier gt lt enum specifier gt or lt typedef name gt Invalid type argument TYPE to sizeof Compile Error You applied sizeof operator to a function type or incomplete struct or union type A function type has no size and the size of an incomplete struct or union type is unknown before its full declaration Invalid type specification Compile Error Combination of type specifiers is incompatible You can use the type specifier short only in combination with int You can use the type specifier long only in combination with int and double You can use the type specifiers signed and unsigned only in combination with one of the basic integer types char short int long Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 23 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 24 National Instruments Corporation Invalid union field declarations Compile Error Compiler encountered an invalid token while processing a struct or union type declaration The compiler expected a token that begins a member type specifier where the type specifier is one of void char short int long float double signed unsigned lt struct or union specifier gt lt enum specifier gt or lt typedef name gt Invalid use of TOKEN Compile Error This error occur
26. stop suspend resume You do this through a function called __RunStateChangeCallback The Notification of Changes in Run State section in Chapter 2 Using Loadable Compiled Modules describes this in detail The run state change callback capability in LabWindows CVI is necessary because when you run a program in the LabWindows CVI development environment it executes as part of the LabWindows CVI process When your program terminates the operating system does not release resources as it does when a process terminates LabWindows CVI releases as many resources as it can but your compiled module might have to do more Also if the program suspends for debugging purposes your compiled module might have to disable interrupts When you run a standalone executable it always executes as a separate process Thus the run state change callback facility is not necessary and does not work External compilers report link errors when you define __RunStateChangeCallback in more than one object file If you require a run state change callback in a compiled module that you intend to use both in LabWindows CVI and an external compiler National Instruments recommends that you put the callback function in a separate source file and create a library a instead of an object file 00ProRef book 06chap05 fm Page 5 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues LabWindows CVI Programmer Reference Manual 5 6 National Instruments Cor
27. 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 25 LabWindows CVI Programmer Reference Manual Library function error STRING NUMBER Non Fatal Run time Error Library function could not perform its task The integer NUMBER is either the function return value or the value of a global variable that explains why the function failed Refer to the library function reference material for more information about the error Lvalue required Compile Error An lvalue is required in this context Ensure that the expression conforms to the semantics of an lvalue Macro expansion too large Compile Error Macro expansion has exceeded the compiler implementation size limitation Macro parameter must follow operator Compile Error operator requires that a macro parameter immediately follow it in a macro replacement list Matching push not encountered or already popped Compile Error pack pragma used a named pop that does not balance with the push of the same name Missing in initialization of TYPE Compile Error Initialization of a struct union or array type is missing a starting for an aggregate initialization value Missing endif Compile Error if ifdef preprocessor directive must have a corresponding endif in the same source file Missing include file name include expects FILE or lt FILE gt Compile Error No include filename
28. 2 MB plus space to accommodate your executable and any files the executable requires Math Coprocessor Software Emulation for Windows 3 1 To run a standalone executable you create using LabWindows CVI for Windows 3 1 your system must have a math coprocessor LabWindows CVI recognizes the following coprocessor emulation programs wemu387 386 from Watcom Q387 from Quickware Distributing Standalone Executables under UNIX The Create Distribution Kit command is not available with UNIX versions of LabWindows CVI However you can use one of several UNIX shell scripts in the misc bin directory of the LabWindows CVI installation directory to package your standalone programs for distribution 00ProRef book 06chap07 fm Page 2 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 3 LabWindows CVI Programmer Reference Manual Distributing Standalone Executables under Solaris 2 To use the System V software packaging utility pkgmk to distribute executable programs under Solaris 2 complete the following steps 1 If your program loads uir files with LoadPanel or loads external modules with LoadExternalModule use caution when you specify the filenames in calls to these functions If you use a relative path the path is relative to the directory that contains the executable Refer to the Location of Files on the Target Machine for Running Executa
29. 23 PM Index National Instruments Corporation I 11 LabWindows CVI Programmer Reference Manual marking imported symbols in include file distributed with DLL 3 23 to 3 24 recommendations 3 24 stack overflow error fatal 1 11 stack size 1 16 to 1 17 standalone executables creating and distributing accessing UIR image and panel state files 7 12 configuring Run time Engine 7 5 to 7 7 distributing Solaris 1 7 4 to 7 5 Solaris 2 7 3 to 7 4 UNIX 7 2 to 7 5 Windows 3 1 7 2 Windows 95 NT 7 1 to 7 2 error checking 7 19 loading files using LoadExternalModule 7 14 to 7 18 DLL files and DLL path files Windows 3 1 7 17 to 7 18 DLL files for Windows 95 NT 7 17 library files 7 16 object modules 7 16 source files 7 18 location of files on target machine 7 9 to 7 19 DLL files Windows 3 1 7 10 to 7 11 Windows 95 NT 7 10 loading files using LoadExternalModule 7 14 to 7 18 Run time Engine under Windows 95 NT 7 10 to 7 11 UIR image and panel state files 7 12 math coprocessor software emulation for Windows 3 1 7 2 relative pathnames for accessing files 7 19 translating message file 7 5 UNIX compiler linker issues 5 3 to 5 5 compatible compilers 5 3 InitCVIRTE called by main function 5 4 to 5 5 non ANSI behavior of Sun Solaris 1 ANSI C library 5 4 printf and scanf under LabWindows CVI 5 4 run state change callbacks not available 5 5 static and shared versions of ANSI C and other Sun librarie
30. 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 3 LabWindows CVI Programmer Reference Manual Anonymous union declared inside parameter list has scope only for this declaration Compile Warning Union declared in the parameter list has scope only within the parameter list As a result its type is incompatible with all other types You must declare the union type before declaring function types that use it Argument 4 must be 0 or 1 Fatal Run time Error Value of the argument to the library function must be 0 or 1 Argument NUMBER must be 0 1 or 2 Fatal Run time Error Value of the argument to the library function must be 0 1 or 2 Argument must be a function pointer to the correct type of callback function Non Fatal Run time Error Argument to the function is not a pointer to the expected type of callback function Argument must be an open stream Fatal Run time Error Argument to the I O library function must be one of the standard streams stdin stdout stderr or a stream you open with the fopen or freopen functions Argument must be character Fatal Run time Error Value of the argument to the library function must be less than 256 Array argument too small Fatal Run time Error Library function requires an array that is larger than the specified argument Make sure you declare or allocate the array with sufficient elements for the fun
31. 5 6 user libraries 2 3 Windows messages passed from DLLs 4 21 GetCVIWindowHandle function 4 21 RegisterWinMsgCallback function 4 21 UnRegisterWinMsgCallback function 4 21 LoadExternalModule rules 7 14 to 7 18 DLL files and DLL path files Windows 3 1 7 17 to 7 18 DLL files Windows 95 NT 3 2 7 17 files listed in project 7 15 to 7 16 forcing modules into executable or DLL 7 15 library files not in project 7 16 object files not in project 7 16 00ProRef book 11Index fm Page 7 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 8 National Instruments Corporation other types of files 7 19 source files 7 18 locking process segments into memory using plock 5 7 long doubles Windows 32 bit DLLs 3 7 low level I O functions using 1 5 low level support driver used by Run time Engine 7 10 to 7 11 M macros predefined 6 1 manual See documentation math coprocessor software emulation for Windows 3 1 7 2 memory protection errors memory corruption fatal 1 11 memory deallocation non fatal 1 11 message file for Run time Engine translating 7 5 Windows 95 NT 7 11 messages passed from DLLs See Windows messages passed from DLLs Microsoft Visual Basic automatic inclusion of Type Library resource for 3 24 to 3 25 Microsoft Visual C C creating 16 bit Windows DLLs 4 21 to 4 22 creating object and library files 3 18 default library directives 3 16 minimum syste
32. 9 5 or later Use the following options when you compile with Watcom IDE Set the Project Target Environment to 32 bit Windows 3 x and set the Image Type to Library lib Turn on the Disable Stack Depth Checking s option Turn on the Change Char Default to Signed j option Add zw d_NI_mswin16_ to the Other Options Turn on the Generate as Needed of option for Stack Frames Turn on the No Debugging Information option Turn on the In line with Coprocessor fpi87 option for Floating Point Model Turn on the Compiler default option for the Memory Model Turn on the 80486 Stack Based Calling 4s option for the Target Processor Use the following compiler flags when using wcc386 or wcc386p zw s 4s j fpi87 d0 of d_NI_mswin16_ You can use optimization flags in addition to the f and you can use other flags such as wn which do not affect the generation of object code Using 32 Bit Borland or Symantec Compiled Modules under Windows 3 1 In this section CVI refers to both LabWindows CVI and Watcom modules while Borland applies to both Borland and Symantec modules The following restrictions apply to Borland object modules Borland packs bit fields in structures differently than CVI so you cannot share structures with bit fields between Borland and CVI Borland returns structures floats and doubles differently than CVI Th
33. An instrument driver consists of a program and a set of function panels The program contains the code for the high level functions Associated with the instrument program is an include file that declares the high level functions you can call the global variables you can access and the defined constants you can use Interactive Execution window A LabWindows CVI work area in which you can execute sections of code without creating an entire program 00ProRef book 10gloss fm Page 4 Monday March 9 1998 3 23 PM Glossary National Instruments Corporation G 5 LabWindows CVI Programmer Reference Manual L list box A dialog box item that displays a list of possible choices lvalue A C expression that refers to an object that can be examined and modified The name lvalue comes from the fact that only lvalues may appear on the left side of an assignment Examples of lvalues are variables parameters array element references such as a i struct element references such as s gt name or s name and pointer dereferences such as ptr Expressions that are not lvalues are called rvalues M MB Megabytes of memory menu An area accessible from the command bar that displays a subset of the possible command choices O output control A function panel control that displays a value that the function you execute generates An output control parameter must be a string an array or a reference parameter of type integer long single
34. C Compiler 5 3 Sun C library See also UNIX compiler linker issues ANSI C implementation 5 8 to 5 9 functions not available 5 9 incompatibilities with LabWindows CVI 5 10 to 5 11 replacement functions table 5 9 calling Sun C library from source code 5 1 restrictions 5 1 LabWindows CVI implementation of printf and scanf 5 4 non ANSI behavior 5 4 static and shared versions 5 3 using low level I O functions 1 5 Sun Solaris distribution of standalone executables LabWindows CVI Run Time Engine files 7 12 Solaris 1 7 4 to 7 5 Solaris 1 patches required 7 5 to 7 6 Solaris 2 7 3 to 7 4 incompatibilities with LabWindows CVI 5 11 support modules for glue code 4 9 Symantec C C creating object and library files 3 19 default directives 3 16 Symantec or Borland 32 bit compiled modules under Windows 4 2 to 4 3 T Target command Build menu 3 20 3 21 3 25 TCP Library 9 6 technical support B 1 to B 2 telephone and fax support numbers B 2 Type Library resource for Visual Basic 3 24 to 3 25 typedefs duplicate 1 4 U uir files See user interface resource uir files unions 1 16 UNIX C library See Sun C library UNIX compiler linker issues 5 1 to 5 11 asynchronous signal handling 5 7 to 5 8 calling Sun C library functions 5 1 restrictions 5 1 creating executables 5 3 to 5 5 compatible external compilers 5 3 InitCVIRTE called by main function 5 4 to 5 5 00ProRef book 11Index fm Page 12
35. CVI you might have to manually define one of these macros External Compiler Versions Supported The following versions of each external compiler work with LabWindows CVI for Windows 95 NT Microsoft Visual C C version 2 2 or higher Borland C C version 4 51 or higher Watcom C C version 10 5 or higher Symantec C C version 7 2 or higher Required Preprocessor Definitions When you use an external compiler to compile source code that includes any of the LabWindows CVI include files add the following to your preprocessor definitions _NI_mswin32_ Multithreading and the LabWindows CVI Libraries Although the LabWindows CVI environment is not multithreaded you can use LabWindows CVI Libraries in the following multithreaded contexts When you call the LabWindows CVI Libraries from a multithreaded executable you create in LabWindows CVI or in an external compiler When you call the LabWindows CVI Libraries from a DLL that a multithreaded executable loads You can create the DLL in LabWindows CVI or in an external compiler When you call the LabWindows CVI Libraries from an object or static library file that you dynamically load in a multithreaded executable You can create the object or library file in LabWindows CVI or in an external compiler All the LabWindows CVI libraries are multithreaded safe when used outside of the LabWindows CVI development environment For detailed info
36. CVI Programmer Reference Manual A 34 National Instruments Corporation Project not linked Link Warning This error occurs when the compiler reports one or more link errors in the Interactive Execution window and the project is not in a linked state This warning provides a possible explanation for the link errors The Interactive Execution window does not link to the project unless the project is in a linked state If you are referencing project symbols from the Interactive Execution window use the Build Project command from the Build menu to compile and link the project first Qualified function type ignored Compile Warning Any qualification of a function declaration is extraneous but harmless Read error Link Error Error has occurred while attempting to read a file Ensure that the file has access permission and that it is in the correct format Redeclaration of s with different calling convention previously declared at w Compile Error Function has been redeclared with a different calling convention Redeclaration of macro parameter NAME Compile Error Parameter name has already been used once by the macro Choose another parameter name Redeclaration of NAME Compile Error Declared name conflicts with a previous declaration in the same scope and name space You have already used the name in this scope Choose another name for this declaration Redeclaration of NAME previously de
37. Easy I O for DAQ Library The Easy I O for DAQ Library functions return a negative value when they detect an error They return a positive value as a warning when they are able to complete their task but not in the way you might expect This library uses a common set of error codes The positive warning codes are the same absolute values as the negative error codes Refer to the LabWindows CVI Standard Libraries Reference Manual or the function panel help for a listing of the error codes and information on the individual functions You can use GetDAQErrorString to get the error message associated with each Easy I O for DAQ Library error or warning code Data Acquisition Library The Data Acquisition Library functions return a negative value when they detect an error They return a positive value as a warning when they are able to complete their task but not in the way you might expect This library uses a common set of error codes The positive warning codes are the same absolute values as the negative error codes Refer to the back of the NI DAQ Function Reference Manual for PC Compatibles or the function panel help for a listing of the error codes You can use GetNIDAQErrorString to get the error message associated with each Data Acquisition Library error or warning code VXI Library The VXI Library uses a variety of global variables and function return codes to report any error that occurs You must check each function description to determine
38. Engine Minimum System Requirements for Windows 95 NT To use a standalone executable or DLL that depends on the LabWindows CVI Run time Engine you must have the following Windows 95 or Windows NT version 4 0 or later A personal computer with at least a 33 MHz 486 or higher microprocessor A VGA resolution or higher video adapter A minimum of 8 MB of memory Free hard disk space equal to 4 MB plus space to accommodate your executable or DLL and any files the executable or DLL requires 00ProRef book 06chap07 fm Page 1 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 2 National Instruments Corporation No Math Coprocessor Required for Windows 95 NT You do not have to have a math coprocessor or emulator to use the LabWindows CVI Run time Engine under Windows 95 NT Minimum System Requirements for Windows 3 1 To run a standalone executable you create using LabWindows CVI for Windows you must have the following MS DOS version 3 1 or later Microsoft Windows operating system version 3 1 or later A personal computer with at least a 25 MHz 386 or higher microprocessor National Instruments recommends a 33 MHz 486 or higher microprocessor A VGA resolution or higher video adapter A math coprocessor A minimum of 4 MB of memory Free hard disk space equal to
39. If you install the LabWindows CVI full development system from CD ROM you can call all the Windows SDK functions Otherwise you can call only a subset of the Windows SDK functions To view help for the SDK functions select the Windows SDK command in the Help menu of any LabWindows CVI window Windows SDK Include Files You must include the SDK include files before the LabWindows CVI include files In this way you avoid problems that arise from function name and typedef conflicts between the Windows SDK and the LabWindows CVI libraries The LabWindows CVI include files contain special macros and conditional compilation to adjust for declarations in the SDK include files Thus LabWindows CVI must process the SDK include files first followed by the LabWindows CVI include files When you compile in LabWindows CVI or when you use an external compiler to compile your source files for linking in LabWindows CVI use the LabWindows CVI SDK include files The LabWindows CVI SDK include files are in the cvi sdk include directory The LabWindows CVI compiler automatically searches the cvi sdk include directory You do not have to add it to your include paths When you use an external compiler to compile and link your source files you must use the SDK include files that come with the external compiler If you use an external compiler to compile your source files for linking in LabWindows CVI use the LabWindows CVI SDK 00ProRef book 06chap03 fm Pa
40. LabWindows CVI under Windows 95 NT or using a compatible external compiler Under Windows 3 1 LabWindows CVI can create only obj files Under UNIX LabWindows CVI can create only o files 00ProRef book 06chap02 fm Page 1 Monday March 9 1998 3 23 PM Chapter 2 Using Loadable Compiled Modules LabWindows CVI Programmer Reference Manual 2 2 National Instruments Corporation Advantages and Disadvantages of Using Loadable Compiled Modules in LabWindows CVI Using compiled modules in LabWindows CVI has the following advantages Compiled modules run faster than source modules Compiled modules do not contain the debugging and user protection code LabWindows CVI generates when it compiles source modules Compiled modules you generate in external compilers can run faster because of optimization LabWindows CVI recompiles the source modules in a project each time you open the project Also if an instrument driver program file is a source module LabWindows CVI recompiles it each time you load the instrument driver LabWindows CVI does not recompile compiled modules when you open a project or load an instrument driver In standalone executables you can dynamically load compiled modules but not source modules You can install compiled modules but not source modules into the Library menu You can provide libraries for other developers without giving them access to your source code Using compiled modules i
41. Retains a Buffer after the Function Returns an Asynchronous Operation If the DLL retains a buffer after the function returns you must modify the glue code source file Suppose two functions exist WriteRealArrayAsync operates just like WriteRealArray except that it returns before it completes writing the real array ClearAsyncWrite terminates the asynchronous I O The glue code interface functions for WriteRealArrayAsync and ClearAsyncWrite should be modified to resemble the following example static DWORD gAsyncWriteAlias gAsyncWriteSize long WriteRealArrayAsync double realArray long numElems long retval unsigned short cw387 DWORD size DWORD alias size numElems sizeof double if Alloc16BitAlias realArray size amp alias lt 0 return lt error code gt cw387 Get387CW retval long InvokeIndirectFunction __static_WriteRealArrayAsync alias numElems Set387CW cw387 if IsError retval replace with macro to check if retval is error Free16BitAlias alias size else gAsyncWriteAlias alias gAsyncWriteSize size return retval 00ProRef book 06chap04 fm Page 11 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 12 National Instruments Corporation long ClearAsyncWrite void because this does no floating point you can remove the cw387 code long retval retval lon
42. To disable the run time checking of argument expressions for a particular call to a library function use the Utility Library function SetBreakOnProtectionErrors Note You cannot use pragmas to disable protection for the functions in the statically linked libraries including User Interface RS 232 TCP DDE Formatting and I O Utility X Property and ANSI C libraries unless you place the DisableLibraryRuntimeChecking pragma at the top of the library header file Details of User Protection Pointer Casting A cast expression consists of a left parenthesis a type name a right parenthesis and an operand expression The cast causes the compiler to convert the operand value to the type that appears within the parenthesis C programmers occasionally have to cast a pointer to one data type to a pointer to another data type Because LabWindows CVI does not restructure the user protection information for each cast expression certain types of cast expressions implicitly disable run time checking for the pointer value In particular casting a pointer expression to the following types disables run time checking on the resulting value Pointer to a pointer AnyType PointerExpression Pointer to a structure struct AnyStruct PointerExpression Pointer to an array AnyType PointerExpression Any non pointer type unsigned PointerExpression int PointerExpression and so on Note An exception exists Casts
43. You must use LoadExternalModule and GetExternalModuleAddr to make such references When you distribute the library or object file as a separate file it is a good idea to place the file in the same directory as the executable or DLL If you place the file in the same directory you can pass a simple filename to LoadExternalModule If you do not want the file to be in the same directory as your executable you must pass a pathname to LoadExternalModule LoadExternalModule interprets relative pathnames as being relative to the directory that contains the executable or DLL 00ProRef book 06chap07 fm Page 16 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 17 LabWindows CVI Programmer Reference Manual Using LoadExternalModule on DLL Files under Windows 95 NT Under Windows 95 NT you cannot pass the pathname of a DLL directly into LoadExternalModule Instead you must pass the pathname of a DLL import library You can link the import library into your executable or DLL or distribute it separately and load it dynamically For import libraries that you link into your executable or DLL refer to the Using LoadExternalModule on Files in the Project section earlier in this chapter For import libraries that you load dynamically refer to the Using LoadExternalModule on Library and Object Files Not in the Project section earlier in this chapter You must always d
44. a incorrect _cvi_freopen stdio h Same as fopen _cvi_realloc stdlib h Does not handle NULL argument properly _cvi_strtol stdlib h Does not set errno to ERANGE on error _cvi_system stdlib h Does not handle NULL argument properly matherr Default behavior prints error message 00ProRef book 06chap05 fm Page 9 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues LabWindows CVI Programmer Reference Manual 5 10 National Instruments Corporation Incompatibilities among LabWindows CVI Sun Solaris and ANSI C Under the ANSI C standard the programmer who implements the library chooses how certain functions behave As a result two implementations of a function can behave differently and still conform to the ANSI standard Because LabWindows CVI now uses the Sun Solaris C library incompatibilities arise from the following sources Differences between LabWindows CVI and the ANSI standard Differences between LabWindows CVI and the Sun Solaris standard This section outlines these incompatibilities Note None of these incompatibilities interfere with development of projects and standalone executables in LabWindows CVI for Sun Between LabWindows CVI and ANSI C The following incompatibilities exist between LabWindows CVI and ANSI C LabWindows CVI for Solaris 1 defines size_t as a signed integer instead of an unsigned integer as the ANSI C standard requires National Instruments
45. a module through the Library Options command you ensure that the library is always available in the LabWindows CVI development environment If you do not want to develop function panels for the library create a fp file without any classes or functions In that case LabWindows CVI loads the library at startup but does not include the library name in the Library menu User libraries must adhere to the requirements outlined for the target operating system Chapter 3 Windows 95 NT Compiler Linker Issues Chapter 4 Windows 3 1 Compiler Linker Issues and Chapter 5 UNIX Compiler Linker Issues of this manual discuss operating system requirements Using a Loadable Compiled Module in the Project List You can include compiled modules directly in the project list Note To use a DLL in your project under Windows 95 NT you must include the DLL import library lib file in the project list rather than the DLL Even when you include a source module in the project list you can instruct LabWindows CVI to create an object module on disk when it compiles the file instead of debuggable code in memory To do this double click in the O column next to the source file in the Project window 00ProRef book 06chap02 fm Page 3 Monday March 9 1998 3 23 PM Chapter 2 Using Loadable Compiled Modules LabWindows CVI Programmer Reference Manual 2 4 National Instruments Corporation Compiled modules must adhere to the requirements outlined for the tar
46. and then dereferenced it You can examine or modify data but you cannot execute it as a function Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 11 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 12 National Instruments Corporation Dereference of function pointer used as data Fatal Run time Error You converted a function pointer to a non function pointer and then dereferenced it You can only execute functions and access them as data Dereference of invalid pointer expression Fatal Run time Error Pointer expression you dereferenced is invalid It is probably the result of a previous invalid pointer operation Dereference of null pointer Fatal Run time Error Pointer expression you dereferenced has the value NULL and cannot be dereferenced Dereference of out of bounds pointer NUMBER bytes NUMBER elements before start of array Fatal Run time Error Pointer expression you dereferenced is invalid because it refers to a location before the start of an array The error message shows the number of bytes and the number of array elements in the array The expression is probably the result of previous illegal pointer arithmetic Dereference of out of bounds pointer NUMBER bytes NUMBER elements past end of array Fatal Run time Error Pointer expression you dereferenced
47. any platform dependent code in your source code using conditional preprocessor directives You can use the built in macros such as _NI_mswin32_ _NI_mswin16_ _NI_mswin_ _NI_unix_ and _NI_sparc_ More information on the macros that LabWindows CVI automatically defines is available in the Compiler Defines section of Chapter 1 LabWindows CVI Compiler Library Issues Avoid using Windows 32 bit SDK functions unless you intend your LabWindows CVI application to run only under Windows 95 NT The sopen and fdopen functions are available only under Windows Avoid using them unless you intend your LabWindows CVI application to run only under Windows Avoid using UNIX host system library calls such as ioctl fcntl and so on unless you intend the LabWindows CVI application to run only under UNIX Refer to the Using the 00ProRef book 06chap06 fm Page 1 Monday March 9 1998 3 23 PM Chapter 6 Building Multiplatform Applications LabWindows CVI Programmer Reference Manual 6 2 National Instruments Corporation Low Level I O Functions section in Chapter 1 LabWindows CVI Compiler of this manual for more information on how to use system library calls Under UNIX the low level I O functions open close read write lseek and eof are available in the UNIX C library Refer to the Using the Low Level I O Functions section Chapter 1 LabWindows CVI Compiler of this manual for more information on how to use UNIX C low level functions These f
48. called The callback function NAME specified in the UIR file is not a known function Non Fatal Run time Error You specified the NAME function as a callback function for an item in a user interface resource file but the function does not exist Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 7 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 8 National Instruments Corporation Calling conventions have no effect on variables calling convention ignored The position of the calling convention modifier may be incorrect Compile Warning You placed a calling convention keyword before a variable name For function pointers you must place the calling convention to the left of the for example int __cdecl funptr Cannot concatenate wide and regular string literals Compile Warning Make sure the string literals you concatenate are either both wide string literals or regular string literals Cannot free memory not allocated by malloc or calloc Fatal Run time Error Pointer value you passed to the function free is invalid because it does not point to dynamic memory allocated by malloc or calloc free can deallocate only pointers you obtain from one of these two functions Cannot generate glue for a function without a prototype NAME Glue Code Generation
49. cannot use the w modifier with the l format specifier Warning Import libraries other than the one for the current compatibility mode may not work for symbols exported from an object file It is recommended that you export using header files instead DLL Link Warning When creating a DLL using the Symbols Marked for Export method for specifying exported symbols one of the modules was an object or library file LabWindows CVI does not have sufficient information to ensure that the import libraries it generates for all four compatible external compilers will have the correct names of the symbols in that module WatchPoint module name is not valid Watchpoint Error Module name you specified in the watch point is not present in the project or in any of the loaded instrument drivers z modifier only valid if rep is present Non Fatal Run time Error z modifier cannot be used if the format specifier is not for an array z modifier required to match string parameter Non Fatal Run time Error If you want to treat a character string as an array of another type you must use the z modifier This error also can occur if the order of the arguments is incorrect or if an argument is missing Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 46 Monday March 9 1998 3 23 PM National Instruments Corporation B 1 LabWindows CVI Programmer Reference Manual
50. if you do not already have one 2 Select the External Compiler Support command in the Build menu of the Project window A dialog box appears 3 In the UIR Callbacks Object File control enter the pathname of the object file you want to generate When you click on the Create button LabWindows CVI generates the object file with a table that contains the names of all the callback functions referenced in all the uir files in the project When you modify and save any of these uir files LabWindows CVI regenerates the object file to reflect the changes 00ProRef book 06chap03 fm Page 11 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 12 National Instruments Corporation 4 Include this object file in the external compiler project you use to create the DLL 5 You must call InitCVIRTE and CloseCVIRTE in your DLLMain function Refer to the Calling InitCVIRTE and CloseCVIRTE section later in this chapter Resolving References from Modules Loaded at Run Time Note This section does not apply unless you use LoadExternalModule to load object or static library files Unlike DLLs object and static library files can contain unresolved references If you call LoadExternalModule to load an object or static library file at run time the Utility Library must resolve those references using function and variable symbols from the LabWindows CVI Run time Engine from
51. is invalid because it refers to a location past the end of an array The error message shows the number of bytes and the number of array elements past the end of the array The expression is probably the result of previous illegal pointer arithmetic Dereference of pointer to freed memory Fatal Run time Error Pointer expression you dereferenced is invalid because it refers to a location in dynamic memory that you deallocated with the free function Once memory is free all pointers into that block of memory become invalid Dereference of unaligned pointer Fatal Run time Error UNIX only Pointer expression you dereferenced is invalid because it points to an address that does not have the proper alignment for the type of the dereferenced object SPARCstation architecture requires that 16 bit objects be halfword aligned 32 bit objects be word aligned and 64 bit objects be doubleword aligned Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 12 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 13 LabWindows CVI Programmer Reference Manual Dereference of uninitialized pointer Fatal Run time Error Pointer expression you dereferenced is invalid because you did not initialize it It is probably an uninitialized local variable You must initialize local variables before you use them Duplicate case la
52. is illegal to take the address amp prefix operator of an object you declare to be of register class Remove the register keyword from the object declaration if you want to apply the address operator to it Invalid pointer argument to library function Fatal Run time Error Pointer expression you passed to the library function is invalid It is probably the result of a previous invalid pointer operation Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 22 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 23 LabWindows CVI Programmer Reference Manual Invalid size for a real Non Fatal Run time Error 4 and 8 are the only valid sizes that you can specify with the b modifier for the f real specifier Invalid size for an integer Non Fatal Run time Error 1 2 and 4 are the only valid sizes that you can specify with the b modifier for the i d x o and c modifiers Invalid storage class Compile Error extern is the only allowable explicit storage class specifier for a function declaration that has block scope Invalid struct field declarations Compile Error Compiler encountered an invalid token while processing a struct or union type declaration The compiler expected a token that begins a member type specifier where the type specifier is one of void char short int long float double
53. item that allows you to toggle between two possible options clipboard A temporary storage area LabWindows CVI uses to hold text that is cut copied or deleted from a work area control An input and output device that appears on a function panel for specifying function parameters and displaying function results cursor The flashing rectangle that shows where you can enter text on the screen cursor location indicator An element of the LabWindows CVI screen that specifies the row and column position of the cursor in the window D default command The action that takes place when you press lt Enter gt and did not specifically select a command A double outline indicates default command buttons in dialog boxes dialog box A prompt mechanism in which you specify additional information necessary to complete a command DLL Dynamic Link Library A file that contains a collection of functions that multiple applications exe files can use E entry mode indicator An element of the LabWindows CVI screen that indicates the current text entry mode as either insert or overwrite excluded code Code that LabWindows CVI ignores during compilation and execution LabWindows CVI displays excluded lines of code in a different color than included lines of code 00ProRef book 10gloss fm Page 2 Monday March 9 1998 3 23 PM Glossary National Instruments Corporation G 3 LabWindows CVI Programmer Reference Manual F fp fi
54. keyword to generate the glue code only Use conditional compilation so that Watcom ignores the PASCAL macro when it compiles Only use standard ANSI C keywords in the h file The keyword PASCAL is the only exception to this rule For example do not use far near or huge If the DLL Requires a Support Module outside the DLL Support modules contain special interface functions that the DLL uses but that exist outside of the DLL If you are unsure whether the DLL requires a support module try to build a project in LabWindows CVI with the DLL in the project list If link errors exist in the form of unresolved references the DLL requires special interface functions Get the source code for the interface functions add it to the glue code and compile using the Watcom compiler If You Pass Arrays Bigger Than 64 K to the DLL If you pass the DLL any arrays bigger than 64 K you must modify the glue code source file For example suppose you have a function in the DLL with the following prototype long WriteRealArray double realArray long numElems 00ProRef book 06chap04 fm Page 9 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 10 National Instruments Corporation In the glue code generated by LabWindows CVI there is a declaration of WriteRealArray like that shown in the following example long WriteRealArray double realArray long numElems
55. label or terminate a compound statement such as Depending on the context of the location of where the compiler issued the diagnostic ensure that the statement syntax is correct for the cases listed above Illegal type array of TYPE Compile Error You attempted to declare an array of functions You probably intended to declare an array of function pointers instead Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 19 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 20 National Instruments Corporation Illegal type const TYPE Compile Error You used more than one qualifier such as const or volatile in a type specification for example const const int Do not use the const and volatile qualifiers more than once each in the same type Illegal type for symbol DllMain TYPE Compile Error DllMain does not conform to the accepted prototype int__stdcall DllMain HINSTANCE hinstDLL DWORD fdwReason LPVOID lpvReserved Illegal type for symbol WinMain TYPE Compile Error WinMain does not conform to the accepted prototype int__stdcall WinMain HINSTANCE hInstance HINSTANCE hPrevInstance LPSTR lpszCmdLine int nCmdShow Illegal type volatile TYPE Compile Error You used more than one qualifier such as const or volatile in a type specification for example co
56. link it in with the rest of the project Ensure that you built the external object file correctly Non terminated address list Fatal Run time Error You attempted to pass an address list array that you did not terminate with 1 to a GPIB 488 2 function that expects the array to terminate with 1 Not enough parameters Non Fatal Run time Error Number of arguments the format string expects is more than the number of arguments you passed in Not enough space for casting expression to TYPE Non Fatal Run time Error Block of memory you obtained from malloc or calloc is not large enough for a single object of type TYPE and cannot be cast to that type Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 28 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 29 LabWindows CVI Programmer Reference Manual Null Pointer Fatal Run time Error Pointer expression you passed to the library function has the value NULL which is not a valid value for the function Null pointer argument to library function Fatal Run time Error Pointer expression you passed to the library function has the value NULL which is not a valid value for the function NUMBER is an illegal array size Compile Error Make sure that the size of the array declaration is gt 0 NUMBER is an illegal bit field size Compil
57. long retval unsigned short cw387 cw387 Get387CW retval long InvokeIndirectFunction __static_WriteRealArray realArray numElems Set387CW cw387 return retval Note The lines of code referencing cw387 are necessary only if the DLL function performs floating point operations They are innocuous and execute quickly so LabWindows CVI adds them to the glue code automatically If the DLL function does not perform floating point operations you can remove these lines If realArray can be greater than 64 K you must modify the interface routine as shown long WriteRealArray double realArray long numElems long retval unsigned short cw387 DWORD size DWORD alias size numElems sizeof double if Alloc16BitAlias realArray size amp alias lt 0 return lt error code gt cw387 Get387CW retval long InvokeIndirectFunction __static_WriteRealArray alias numElems Set387CW cw387 Free16BitAlias alias size return retval 00ProRef book 06chap04 fm Page 10 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 11 LabWindows CVI Programmer Reference Manual You must also modify the call to GetIndirectFunctionHandle for WriteRealArray as shown in the following code if __static_WriteRealArray GetIndirectFunctionHandle fp INDIR_PTR INDIR_WORD INDIR_ENDLIST by changing INDIR_PTR to INDIR_DWORD If the DLL
58. memory using plock 5 7 program entry points Windows 1 5 Project window Run Options menu 4 4 projects See also source files loadable compiled modules in project list 2 3 to 2 4 loading project files with LoadExternalModule 7 15 to 7 16 pth files loading with LoadExternalModule 7 17 to 7 18 not supported for Windows 95 NT 3 2 using with standalone executables 7 9 Q Q387 coprocessor emulation software Quickware 7 2 R references resolving See callback references resolving Windows 95 NT RegisterWinMsgCallback function 4 21 Reload DLLs Before Each Run option 4 4 resolving references See callback references resolving 00ProRef book 11Index fm Page 9 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 10 National Instruments Corporation resource files Windows 95 NT for standalone executables 7 11 return values missing non fatal error 1 11 RS 232 Library 9 5 Run Options command Options menu Break on library errors option 1 12 7 19 setting debugging levels 1 8 setting maximum stack size 1 16 Run Options menu Project window 4 4 run state change notification for compiled modules asynchronous callbacks 2 4 examples of program state changes 2 5 to 2 6 including in DLLs 3 2 to 3 3 prototype for callback 2 4 requirements 2 4 unavailable for executables under UNIX 5 5 for external compilers under Windows 95 NT 3 13 to 3 14 Run time Engine Se
59. of the pointer expressions in the subtraction is invalid because it does not point into an array Both expressions in pointer subtractions must point into the same object Pointer to a local is an illegal return value Compile Error Value returned from the function is a pointer to a parameter or local variable Because the lifetime of a parameter or local variable ends when you return from the function any pointer to such an object is invalid Pointer to a parameter is an illegal return value Compile Error Value returned from the function is a pointer to a parameter or local variable Because the lifetime of a parameter or local variable ends when you return from the function any pointer to such an object is invalid Pointer to free memory passed to library function Fatal Run time Error Pointer expression you passed to the library function is invalid because it refers to a location in dynamic memory that you deallocated with the function free Once memory is free all pointers into that block of memory are invalid pragma pack pop does not set alignment Use separate pack pragma Compile Warning You used a pragma pop with an alignment value Use separate pack pragmas for popping and setting the alignment value Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 33 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows
60. of your program in LabWindows CVI try using SIGINT or SIGQUIT If sending the SIGINT or SIGQUIT signal fails you must use the stronger SIGTERM signal which terminates not just your program but also LabWindows CVI Note Some signals can cause LabWindows CVI to dump core you are running a program that does not install handlers for them Solaris 1 ANSI C Library Implementation The C library that comes with Sun Solaris 1 SunOS 4 1 x does not comply with the ANSI C standard as follows Some ANSI C functions are missing from the library Some library functions have different behavior than the ANSI standard specifies LabWindows CVI corrects these problems by linking your programs to a supplemental C library libcfix a which is in the lib subdirectory of the LabWindows CVI installation directory This library contains replacement functions for some Sun Solaris functions and for the ANSI functions that are not available in the Sun Solaris library The names of the replacement functions differ from the Sun Solaris function names and do not interfere with programs or libraries that depend upon the non ANSI behavior of some Sun Solaris functions The LabWindows CVI ANSI header files contain macro definitions for the replacement functions When you compile with the LabWindows CVI headers your program references the LabWindows CVI replacement functions instead of the Sun Solaris versions Consider the case of realloc which LabWindows CV
61. prog_buf 100 status ibrd ud instr_buf 200 Scan instr_buf 100d b2o01 gt 100d b2 prog_buf If you use a GPIB instrument that sends two byte binary data in Motorola byte order use Scan as shown in the following example Scan instr_buf 100d b2o10 gt 100d b2 prog_buf In either case use the o modifier only on the buffer that contains the raw data from the instrument instr_buf LabWindows CVI ensures that the program buffer prog_buf uses the proper byte order for the host processor For a full description of the o modifier refer to Chapter 2 Formatting and I O Library of the LabWindows CVI Standard Libraries Reference Manual 00ProRef book 06chap06 fm Page 2 Monday March 9 1998 3 23 PM Chapter 6 Building Multiplatform Applications National Instruments Corporation 6 3 LabWindows CVI Programmer Reference Manual Externally Compiled Modules Although you can use externally compiled modules in LabWindows CVI as this manual describes the best medium for application portability is ANSI C source code Object modules are not directly portable from one platform to another because the object file formats on the various platforms differ For example the object file formats are different among Windows 3 1 Windows 95 NT and UNIX systems Although SPARCstations have the same computer architecture Solaris 1 x Sun OS 4 x and Solaris 2 x also use different object file formats that make object modules n
62. program at a time Windows 3 1 loads extra copies of this special executable into memory Under Windows 95 NT the LabWindows CVI run time libraries come in DLL form Standalone executables you create in LabWindows CVI and executables you create in external compilers use the same DLLs If you run more than one program at a time Windows 95 NT loads only one copy of the DLL To create a standalone executable you must first select Standalone Executable from the submenu attached to the Target command in the Build menu of the Project window When you select Standalone Executable the Create Standalone Executable command appears below the Target command in the Build menu The Create Standalone Executable command under Windows 95 NT is the same as under Windows 3 1 except that you also can specify version information to include in the executable in the form of a standard Windows version resource Creating DLLs in LabWindows CVI In LabWindows CVI for Windows 95 NT you can create 32 bit DLLs Along with each DLL LabWindows CVI creates a DLL import library for your compatible compiler You can choose to create DLL import libraries compatible with all four external compilers You must have a separate project for each DLL you want to create Select Dynamic Link Library from the submenu attached to the Target command in the Build menu of the Project window When you select Dynamic Link Library the Create Dynamic Link Library command appears below the Tar
63. run in LabWindows CVI does not call RunUserInterface GetUserEvent or scanf or if it does not return from a User Interface Library callback events will not be processed You can remedy this in the program by periodically calling the User Interface Library function ProcessSystemEvents Creating 16 bit DLLs with Microsoft Visual C 1 5 Be sure to consider the following issues or project options when you create a DLL with Microsoft Visual C 1 5 Every function you call from outside the DLL must be far exported and must load the data segment into the DS register The function must load the DS register if you want to use any non local variables in a function Use the large or huge memory model The savings you gain by using smaller memory models is not worth having to use the far keyword throughout your code This project option is in Compiler Memory Model Segment Setup You can make the compiler load the data segment into the DS register automatically by using the SS DS DS loaded on function entry project option in Compiler Memory Model Segment Setup If you try to use the optimize entry code option GD by selecting Compiler Windows Prolog Epilog Generate Prolog Epilog For it conflicts with the 00ProRef book 06chap04 fm Page 21 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 22 National Instruments Corporation Au optio
64. size of an incomplete type is unknown storage cannot be allocated for the object Undefined size for field TYPE Compile Error Member field declaration has no size for the declared type You probably declared the member with an empty struct or union type declaration Undefined size for field TYPE NAME Compile Error Member field declaration has no size for the declared type You probably declared the member with an empty struct or union type declaration Undefined size for parameter TYPE NAME Compile Error You declared a parameter with an incomplete type Because the size of an incomplete type is unknown storage cannot be allocated for the object Undefined size for static TYPE NAME Compile Error You declared a static object with an incomplete type or without an initialization expression from which the compiler can calculate a size for the type Because the size of an incomplete type is unknown you cannot allocate storage for the object Undefined static TYPE NAME Compile Warning or Error You declared the static function but never defined it Because a static function is only visible within the file in which you declared it you must define it at some point within the file in order to use it If you called the function anywhere in the file this diagnostic is an error Otherwise it is a warning Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef bo
65. structure definition struct t double d1 char charVal short shortVal double d2 If the maximum alignment is 1 the compiler can start the structure on any 1 byte boundary and inserts no gaps between the structure elements If the maximum alignment is 8 the compiler must start the structure on an 8 byte boundary place shortVal on a 2 byte boundary and place d2 on an 8 byte boundary 00ProRef book 06chap01 fm Page 4 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 5 LabWindows CVI Programmer Reference Manual You can set the maximum alignment as follows pragma pack 4 sets maximum alignment to 4 bytes pragma pack 8 sets maximum alignment to 8 bytes pragma pack resets to the default The maximum alignment the compiler applies to a structure is based on the last pack pragma statement it sees before the definition of the structure Program Entry Points Windows 95 NT Only Under Windows 95 NT you can use WinMain instead of main as the entry point function to your program You might want to do this if you plan to link your executable using an external compiler You must include windows h for the data types that normally appear in the WinMain parameter list The following is the prototype for WinMain with the Windows data types reduced to intrinsic C types int __stdcall WinMain void hInstance void hPrevInstance char lpszCmdLine int
66. the compiler found TOKEN1 instead of TOKEN2 The __cdecl calling convention is not supported with functions returning floats doubles or structures in WATCOM Compatibility Mode Compile Error Function with an explicit __cdecl qualifier returns a double float or structure and your current compatible compiler is Watcom Either remove the qualifier or change the function The callback function NAME differs only by a leading underscore from another function or variable Change one of the names for proper linking Non Fatal Run time Error When trying to match a callback name you specified in a uir file to the callback function the compiler found two symbols that are the same except for a leading underscore Resolve this ambiguity by changing one of the names Thread data is not supported Compile Error You cannot implement thread local storage in LabWindows CVI Too many arguments to FUNCTION Compile Error Declaration for function FUNCTION contains fewer parameters than the number of arguments you passed in this function call Too many arguments to variable argument function Non Fatal Run time Error You passed more arguments to the variable argument function than it expected The extra arguments do not affect the function call in any way Too many function parameters Compile Error Number of parameter declarations exceeds compiler limitations Declare the function with fewer pa
67. the function EnterAsyncCallback and ExitAsyncCallback have one parameter which is a pointer to a buffer of size ASYNC_CALLBACK_ENV_SIZE You must pass the same buffer into ExitAsyncCallback that you passed into EnterAsyncCallback because the buffer stores state information The definition of ASYNC_CALLBACK_ENV_SIZE and the prototypes for these two functions are in libsupp h 00ProRef book 06chap02 fm Page 7 Monday March 9 1998 3 23 PM National Instruments Corporation 3 1 LabWindows CVI Programmer Reference Manual 3 Windows 95 NT Compiler Linker Issues This chapter describes the different kinds of compiled modules available under LabWindows CVI for Windows 95 NT and includes programming guidelines for modules you generate with external compilers Under Windows 95 NT the LabWindows CVI compiler is compatible with four external 32 bit compilers Microsoft Visual C C Borland C C Watcom C C and Symantec C C This manual refers to the four compilers as the compatible external compilers In LabWindows CVI under Windows 95 NT you can do the following Load 32 bit DLLs through the standard import library mechanism Create 32 bit DLLs and DLL import libraries Create library files and object files Call the LabWindows CVI libraries from executables or DLLs created with any of the four compatible external compilers Create object files library files and DLL import libraries that the compatib
68. the startup code into your application or DLL Instead it requires the module that contains main WinMain or DllMain to reference a special symbol that the appropriate startup code module resolves The Watcom compiler automatically generates a reference to the special symbol into any module that contains main WinMain or DllMain This symbol is __DLLstart_ _wstart2_ or _cstart_ depending on whether the project is for a DLL Windows application or console application respectively Object modules compiled in LabWindows CVI do not contain such references LabWindows CVI cannot generate the correct reference because it makes no distinction between console and non console applications You must include the symbol reference in your object file explicitly For example if your module contains the main function you can generate the correct symbol reference by adding the following to the source code for the module extern int _cstart_ void dummy amp _cstart_ 00ProRef book 06chap03 fm Page 17 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 18 National Instruments Corporation Creating Object and Library Files in External Compilers for Use in LabWindows CVI When you use a compatible external compiler to create an object or library file for use in LabWindows CVI you must use the include files in the cvi include and cvi sdk include directories Ensure that t
69. the type Ensure that the value does not exceed the maximum value for the expression type Overflow in floating constant CONSTANT Compile Warning Value of a constant or constant expression exceeds the limits of the type Ensure that the value does not exceed the maximum value for the expression type Overflow in hexadecimal escape sequence Compile Warning Value of a constant or constant expression exceeds the limits of the type Ensure that the value does not exceed the maximum value for the expression type Overflow in octal escape sequence Compile Warning Value of a constant or constant expression exceeds the limits of the type Ensure that the value does not exceed the maximum value for the expression type Overflow in value for enumeration constant CONSTANT Compile Error Value of a constant or constant expression exceeds the limits of the type Ensure that the value does not exceed the maximum value for the expression type Overflow occurred during the conversion of the int The absolute value is too big for the size Non Fatal Run time Error Number was too large to store in the integer of the specified size Overflow occurred during the conversion of the float The number is too big for type float Non Fatal Run time Error Number was too large to store in a 4 byte real Overflow occurred during the conversion of the int The signed value is too big for the size Non Fatal
70. what error checking might be necessary Refer to the specific VXI function reference manual or the on line help for a listing of the error codes GPIB GPIB 488 2 Library The GPIB libraries return status information through two global variables called ibsta and iberr Note If your program uses multiple threads use the ThreadIbsta and ThreadIberr functions in place of the ibsta and iberr global variables Note The GPIB Library functions return the same value that they assign to ibsta You can choose to use either the return values ibsta or ThreadIbsta The ERR bit within ibsta indicates an error condition If this bit is not set iberr does not contain meaningful information If the ERR bit is set in ibsta the error condition is stored in 00ProRef book 06chap09 fm Page 4 Monday March 9 1998 3 23 PM Chapter 9 Checking for Errors in LabWindows CVI National Instruments Corporation 9 5 LabWindows CVI Programmer Reference Manual iberr After each GPIB call your program should check whether the ERR bit is set to determine if an error has occurred as shown in the following code segment if ibwrt bd instrID buf cnt amp ERR PREFIX_err 230 Refer to your NI 488 2 Function Reference and user manuals for detailed information on GPIB global variables and listings of status and error codes LabWindows CVI function panel help also has listings of status and error codes RS 232 Library The RS 232 library returns stat
71. you the developer and the user of your executable program Feel free to use the text in this section in the documentation for your executable program Solaris 1 Patches Required for Running Standalone Executable Executables you create using LabWindows CVI do not run properly on some versions of Solaris 1 SunOS 4 unless you patch the dynamic linker usr lib ld so For this reason you might have to patch the operating system on the machine on which you install your standalone executable The required patches are available from Sun and also come with LabWindows CVI You can either install the patch automatically using the installation script in the directory that contains the patch or you may install the patch manually by following the instructions that come with 00ProRef book 06chap07 fm Page 5 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 6 National Instruments Corporation the patch The required patches are available in the misc patch subdirectory of the LabWindows CVI installation directory The following patches are available Patch ID 100257 06 for SunOS 4 1 3 4 1 3c Patch ID 101743 02 for SunOS 4 1 3_U1 Patch ID 101783 02 for SunOS 4 1 1 4 1 2 Configuration Option Descriptions The Run time Engine recognizes various configuration options Under Windows platforms the installation program for the Run
72. 0 rules for using 7 13 using run state change callbacks 2 6 to 2 7 Windows 95 NT 32 bit DLLS See Windows 32 bit DLLs calling convention qualifiers in function declarations 1 2 to 1 3 calling SDK functions in LabWindows CVI 3 26 to 3 28 automatic loading of SDK import libraries 3 27 to 3 28 creating multiple threads using Windows SDK functions 3 27 SDK include files 3 26 to 3 27 user interface capabilities 3 27 compatibility with external compilers 3 4 to 3 8 choosing a compiler 3 5 DLLs 3 5 external compiler versions supported 3 8 LabWindows CVI differences 3 7 to 3 8 object files library files and DLL import libraries 3 5 required preprocessor definitions 3 8 compiler linker issues calling SDK functions 3 26 to 3 28 compatibility with external compilers 3 4 to 3 8 creating DLLs 3 20 to 3 25 00ProRef book 11Index fm Page 15 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 16 National Instruments Corporation creating executables 3 20 creating object and library files in external compilers 3 18 to 3 19 creating object files 3 26 creating static libraries 3 25 hardware interrupts 3 29 LabWindows CVI libraries in external compilers 3 9 to 3 15 loading 32 bit DLLs 3 1 to 3 4 multithreading 3 8 object and library files in external compilers 3 15 to 3 17 setting up include paths 3 28 to 3 29 creating object and library files in external compiler 3 18 to 3
73. 0 bytes In the other compilers they are 8 bytes In LabWindows CVI they are always 8 bytes Avoid using long double in your DLL API Differences between LabWindows CVI and the External Compilers LabWindows CVI does not work with all the non ANSI extensions each external compiler provides Also in cases where ANSI does not specify the exact implementation LabWindows CVI does not always agree with the external compilers Most of these differences are obscure and rarely encountered The following are the most important differences you might encounter wchart_t is only one byte in LabWindows CVI 64 bit integers do not exist in LabWindows CVI long double values are 10 bytes in Borland C C but 8 bytes in LabWindows CVI You cannot use structured exception handling in LabWindows CVI You cannot use the Watcom C C __cdecl calling convention in LabWindows CVI for functions that return float or double scalar values or structures In Watcom __cdecl is not the default calling convention LabWindows CVI does not define _MSC_VER __BORLANDC__ __WATCOMC__ and __SC__ The external compilers each define one of these macros If you port code 00ProRef book 06chap03 fm Page 7 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 8 National Instruments Corporation originally developed under one of these external compilers to LabWindows
74. 19 Borland C C 3 18 Microsoft Visual C C 3 18 Symantec C C 3 19 Watcom C C 3 19 creating object files in LabWindows CVI 3 26 creating static libraries in LabWindows CVI 3 25 cvidir option for configuring Run time Engine 7 7 distributing standalone executables coprocessor not required 7 2 creating in LabWindows CVI 3 20 location of files 7 10 to 7 11 low level support driver 7 10 to 7 11 message resource and font files 7 11 minimum system requirements 7 1 National Instruments hardware I O libraries 7 11 Run time Library DLLs 7 10 system requirements 7 1 to 7 2 hardware interrupts 3 29 LabWindows CVI libraries in external compilers 3 9 to 3 15 calling InitCVIRTE and CloseCVIRTE 3 14 to 3 15 include files 3 10 resolving callback references from uir files 3 10 to 3 12 resolving references from modules loaded at run time 3 12 to 3 13 run state change callbacks unavailable 3 13 to 3 14 standard input output window 3 10 Watcom stack based calling convention 3 15 multithreading and LabWindows CVI libraries 3 8 program entry points 1 5 setting up include paths for LabWindows CVI ANSI C and SDK libraries 3 28 to 3 29 structure packing pragmas 1 4 to 1 5 using object and library files in external compiler 3 15 to 3 17 Borland C Builder 3 17 Borland incremental linker 3 17 Borland static versus dynamic C libraries 3 17 default library directives 3 15 to 3 16 Borland C C 3 16 Micros
75. 2 DDE TCP RS 232 Utility and C system libraries stdcall A Windows 95 NT calling convention in which function calls pass arguments from right to left and the function restores the stack pointer before it returns String Display window A window for viewing and editing string variables and arrays T text box A dialog box item in which you enter text from the keyboard or view text U User Interface Editor window The window in which you build pull down menus dialog boxes panels and controls and save them to a User Interface Resource uir file The LabWindows CVI User Interface Reference Manual describes it V Variables window A window that shows the values of the variables that are currently active 00ProRef book 10gloss fm Page 7 Monday March 9 1998 3 23 PM Glossary LabWindows CVI Programmer Reference Manual G 8 National Instruments Corporation W Watch window A window that shows the values of selected variables and expressions that are currently active window A working area that supports specific tasks related to developing and executing programs 00ProRef book 10gloss fm Page 8 Monday March 9 1998 3 23 PM National Instruments Corporation I 1 LabWindows CVI Programmer Reference Manual Index Special Characters Numbers line preprocessor directive 1 2 _cdecl calling convention qualifier 1 2 __cdecl calling convention qualifier 1 2 __declspec dllexport qualifier 1 3 3 22
76. 3 23 PM National Instruments Corporation v LabWindows CVI Programmer Reference Manual Contents About This Manual Organization of This Manual xiii Conventions Used in This Manual xiv Related Documentation xv Customer Communication xvi Chapter 1 LabWindows CVI Compiler Overview 1 1 LabWindows CVI Compiler Specifics 1 1 Compiler Limits 1 1 Compiler Options 1 2 Compiler Defines 1 2 C Language Non Conformance 1 2 C Language Extensions 1 2 Keywords That Are Not ANSI C
77. 422 Up to 14 400 baud 8 data bits 1 stop bit no parity United Kingdom 01635 551422 Up to 9 600 baud 8 data bits 1 stop bit no parity France 01 48 65 15 59 Up to 9 600 baud 8 data bits 1 stop bit no parity FTP Support To access our FTP site log on to our Internet host ftp natinst com as anonymous and use your Internet address such as joesmith anywhere com as your password The support files and documents are located in the support directories 00ProRef book 09CCApx fm Page 1 Monday March 9 1998 3 23 PM LabWindows CVI Programmer Reference Manual B 2 National Instruments Corporation Fax on Demand Support Fax on Demand is a 24 hour information retrieval system containing a library of documents on a wide range of technical information You can access Fax on Demand from a touch tone telephone at 512 418 1111 E Mail Support Currently USA Only You can submit technical support questions to the applications engineering team through e mail at the Internet address listed below Remember to include your name address and phone number so we can contact you with solutions and suggestions support natinst com Telephone and Fax Support National Instruments has branch offices all over the world Use the list below to find the technical support number for your country If there is no National Instruments office in your country contact the source from which you purchased your software to obtain support Country Telephon
78. 6 bit compiler and 4 bytes on a 32 bit compiler This is why you do not have to make any modifications if the specifier for a variable of type int is d without the bn modifier All pointers are 32 bit offsets LabWindows CVI does not use the far pointers that have both a segment selector and an offset except in 16 bit Windows DLLs under Windows 3 1 LabWindows CVI for Windows 3 1 calls 16 bit DLLs through a special interface LabWindows CVI generates from the header file for the DLL For more information refer to the Using 32 Bit Watcom Compiled Modules under Windows 3 1 and 16 Bit Windows DLLs sections in Chapter 4 Windows 3 1 Compiler Linker Issues 00ProRef book 06chap01 fm Page 7 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 8 National Instruments Corporation Debugging Levels You can compile the source modules in your application to include debugging information If you do so you can use breakpoints and view or modify variables and expressions while your program is suspended You set the debugging level by selecting Options Run Options in the Project window Refer to the Run Options section in Chapter 3 Project Window of the LabWindows CVI User Manual for information on debugging levels User Protection User protection detects invalid program behavior that LabWindows CVI cannot otherwise detect during compilation LabWindows CVI reports such invalid program b
79. 9 4 Edit menu Function Tree Editor 8 2 Source Interactive Execution and Standard Input Output windows 3 3 electronic support services B 1 to B 2 e mail support B 2 enum sizes Windows 32 bit DLLs 3 7 error checking 9 1 to 9 7 Break on Library Errors option 1 12 7 19 9 1 overview 9 1 standalone executables 7 19 status codes checking function call status codes 9 1 returned by LabWindows CVI functions 9 2 to 9 3 status reporting by libraries and instrument drivers 9 3 to 9 7 errors See also user protection errors compiler related error messages A 1 to A 46 events multiplatform application considerations 6 3 executable file required for standalone executables 7 8 executables creating and distributing See standalone executables creating and distributing export qualifiers _export 1 3 __export 1 3 3 22 exporting DLL functions and variables 3 22 purpose and use 1 3 to 1 4 External Compiler Support command Build menu 3 11 3 13 external modules See also loadable compiled modules definition 2 4 forcing referenced modules into executable or DLL 7 15 multiplatform application considerations 6 3 under UNIX compiling with external compilers 5 6 to 5 7 restrictions 5 6 using loadable compiled module as 2 4 00ProRef book 11Index fm Page 4 Monday March 9 1998 3 23 PM Index National Instruments Corporation I 5 LabWindows CVI Programmer Reference Manual F fax and telephone suppor
80. 98 3 23 PM About This Manual LabWindows CVI Programmer Reference Manual xiv National Instruments Corporation Chapter 7 Creating and Distributing Standalone Executables and DLLs describes how the LabWindows CVI Run time Engine DLLs externally compiled modules and other files interact with your executable file This chapter also describes how to perform error checking in a standalone executable program You can create executable programs from any project that runs in the LabWindows CVI environment Chapter 8 Distributing Libraries and Function Panels describes how to distribute libraries add libraries to a user s Library menu and specify library dependencies Chapter 9 Checking for Errors in LabWindows CVI describes LabWindows CVI error checking and how LabWindows CVI reports errors in LabWindows CVI libraries and compiled external modules Appendix A Errors and Warnings contains an alphabetized list of compiler warnings compiler errors link errors DLL loading errors and external module loading errors generated by LabWindows CVI Appendix B Customer Communication contains forms to help you gather the information necessary to help us solve your technical problems and a form you can use to comment on the product documentation The Glossary contains an alphabetical list of terms used in this manual and a description of each The Index contains an alphabetical list of key terms a
81. Assume the following DLL functions int f char ptrs struct x char name int g struct x ptr For the function f the glue code that LabWindows CVI generates converts the pointer to the array ptrs to a 16 bit far pointer when you pass it to the DLL function but does not convert the pointers inside the array ptrs 0 ptrs 1 Similarly for the function g the glue code that LabWindows CVI generates converts the pointer to the structure ptr but not the pointer inside the structure name If your DLL has functions with these types of parameters then your DLL cannot use glue code automatically generated at load time You can use the Generate DLL Glue Source command to generate glue code and then modify it in the following manner 1 Before the call to InvokeIndirectFunction a Save the hidden pointer in a local variable b Replace the hidden pointer with a 16 bit alias by calling Alloc16BitAlias 2 After the call to InvokeIndirectFunction a Free the 16 bit alias by calling Free16BitAlias b Restore the hidden pointer with the value you saved in step 1 For the functions f and g the glue code that LabWindows CVI generates looks like the following excerpt int f char ptrs int retval unsigned short cw387 cw387 Get387CW retval int InvokeIndirectFunction __static_f ptrs Set387CW cw387 return retval int g struct x ptr int retval unsigned short cw387 00ProRef
82. CPTR CallbackHelper CallbackData UserDefinedProcHandle goto failed CallbackData proc16Instance MakeProcInstance CallbackData proc16 GetTaskInstance cw387 Get387CW retval long InvokeIndirectFunction __static_InstallCallback CallbackData proc16Instance Set387CW cw387 return retval 00ProRef book 06chap04 fm Page 14 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 15 LabWindows CVI Programmer Reference Manual failed FreeCallbackResources return FALSE Call this function after unregistering the callback void FreeCallbackResources void if CallbackData proc16Instance FreeProcInstance CallbackData proc16Instance CallbackData proc16Instance 0 if CallbackData proc16 ReleaseProc16 CallbackData proc16 CallbackData proc16 0 if CallbackData UserDefinedProcHandle FreeProcUserDefinedHandle CallbackData UserDefinedProcHandle CallbackData UserDefinedProcHandle 0 If the DLL Returns Pointers DLLs return pointers that fall into the following two classes Pointers to memory that LabWindows CVI allocates that you pass into the DLL and that the DLL later returns You must map these pointers back into normal 32 bit pointers that you can use in LabWindows CVI code Use the function MapAliasToFlat to convert these pointers Pointers to memory that a DLL allocates Because these poi
83. Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 19 LabWindows CVI Programmer Reference Manual Rules for Accessing Other Files The functions for accessing files such as fopen OpenFile SetFileAttrs DeleteFile and so on interpret relative pathnames as being relative to the current working directory Under Windows the initial current working directory is normally the directory of the executable However if a different directory exists in the Working Directory or Start In field of the Properties dialog box for the executable then it is the initial current working directory Under UNIX the initial current working directory is the directory from which you invoke the executable You can create an absolute path for a file in the executable directory by using GetProjectDir and MakePathname Error Checking in Your Standalone Executable or DLL Usually you enable debugging and the Break on Library Errors option while you develop your application in LabWindows CVI With these features enabled LabWindows CVI checks for programming errors in your source code Consequently you might have a tendency to relax your own error checking When you create a standalone executable program or DLL all your source modules are compiled Compiled modules always disable debugging and the Break on Library Errors option resulting in smaller and faster code Thus you must perform your own error checking w
84. Error In order to generate glue code for a DLL function you must specify a complete prototype for the function You must specify the types of the parameters in the prototype Cannot generate glue for a static function FUNCTION Glue Code Generation Error You cannot export static functions in a DLL so it is useless to generate glue code for them Cannot generate glue for a variable argument function FUNCTION Glue Code Generation Error In LabWindows CVI for Windows 3 1 you cannot use DLL functions that accept a variable number of arguments Cannot initialize undefined TYPE Compile Error You attempted to initialize a declaration of an incomplete struct or union type such as a struct or union type whose members you have not yet specified Ensure that the initialization appears after the full struct or union declaration Cannot link variable NAME to import library without __import keyword in declaration Link Error Variable that you have declared as extern is defined in a DLL import library but you did not include the __import qualifier in the declaration Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 8 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 9 LabWindows CVI Programmer Reference Manual Cannot link variable NAME to import library without declspec dllimport keyword in
85. ExternalModule 7 16 using with standalone executables 7 9 library function user protection errors 1 16 disabling 1 13 to 1 14 Library menu appearance of user libraries on 2 3 installing user libraries 2 3 8 1 to 8 2 linking modules with external modules 7 15 Library Options command Project Options menu 2 3 8 1 library protection errors 1 11 to 1 12 disabling for functions 1 13 to 1 14 at run time 1 12 errors involving library protection 1 11 to 1 12 loadable compiled modules 16 bit Windows DLLs creating with Borland C 4 22 with Microsoft Visual C 1 5 4 21 to 4 22 glue code DLLs unable to use glue code generated at load time 4 8 to 4 20 DLLs using glue code generated at load time 4 8 requirements 4 7 helpful LabWindows CVI options 4 4 overview 4 3 to 4 4 rules and restrictions 4 5 to 4 7 search precedence 4 23 to 4 24 32 bit Borland or Symantec compiled modules under Windows 4 2 to 4 3 32 bit Watcom compiled modules under Windows 3 1 4 1 to 4 2 advantages and disadvantages 2 2 external modules 2 4 instrument driver program files 2 2 to 2 3 modules compiled by LabWindows CVI 4 1 multiplatform application considerations 6 3 notification of run state changes 2 4 to 2 6 examples of program state changes 2 5 to 2 6 modules using asynchronous callbacks 2 4 overview 2 1 project list 2 3 to 2 4 requirements 2 1 UNIX compiler linker issues 5 6 to 5 7 compiling 5 6 to 5 7 restrictions
86. H environment variable 2 Look for a dll file in the directory of the executable The dll file must have the same base name as the file in the project or as the instrument driver 3 Otherwise use the standard Windows DLL search algorithm Note Before searching for a dll file the Run time Engine always looks for a pth file Therefore your choice of whether to use a pth file when you develop your application in the LabWindows CVI environment does not restrict your choice of whether to use a pth file in the standalone application Rules for Loading Files Using LoadExternalModule LoadExternalModule can load the following file types Library Files lib Windows or a UNIX Object Modules obj Windows or o UNIX DLL Import Library Files lib Windows 95 NT only DLL Path Files pth Windows 3 1 only DLL Files dll Windows 3 1 only Source Files c linked into your executable or DLL 00ProRef book 06chap07 fm Page 14 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 15 LabWindows CVI Programmer Reference Manual Forcing Modules that External Modules Refer to into Your Executable or DLL In the LabWindows CVI development environment external modules can link to modules in the Instrument and Library menus regardless of whether you refer to them elsewhere in your project However when you create a standalon
87. I Compiler describes LabWindows CVI compiler specifics C language extensions 32 bit compiler issues debugging levels and user protection Chapter 2 Using Loadable Compiled Modules describes the advantages and disadvantages of using compiled code modules in your application It also describes the kinds of compiled modules available in LabWindows CVI and includes programming guidelines for modules you generate with external compilers Chapter 3 Windows 95 NT Compiler Linker Issues describes the different kinds of compiled modules available under LabWindows CVI for Windows 95 NT and includes programming guidelines for modules you generate with external compilers Chapter 4 Windows 3 1 Compiler Linker Issues describes the different kinds of compiled modules available under LabWindows CVI for Windows 3 1 and includes programming guidelines for modules you generate with external compilers Chapter 5 UNIX Compiler Linker Issues describes the kinds of compiled modules available under LabWindows CVI for UNIX and includes programming guidelines for modules you generate with external compilers Chapter 6 Building Multiplatform Applications contains guidelines and caveats for writing platform independent LabWindows CVI applications LabWindows CVI currently runs under Windows 3 1 and Windows 95 NT for the PC and Solaris 1 and Solaris 2 for the SPARCstation 00ProRef book 05atm fm Page xiii Monday March 9 19
88. I replaces with _cvi_realloc The Sun Solaris 1 implementation of the realloc function fails when the first argument is NULL The ANSI standard requires that realloc accept NULL as a first argument In the library libcfix a LabWindows CVI defines _cvi_realloc which treats a NULL argument as the ANSI standard prescribes The LabWindows CVI header file stdlib h 00ProRef book 06chap05 fm Page 8 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues National Instruments Corporation 5 9 LabWindows CVI Programmer Reference Manual contains the following macro definition so that _cvi_realloc replaces all references to realloc in your program define realloc _cvi_realloc Note Object files you previously compiled using either older LabWindows CVI headers or Sun Solaris headers do not reference the replacement functions You must recompile your object files using LabWindows CVI headers to obtain ANSI compliant behavior The following lists show the complete contents of the supplemental C library libcfix a Replacement Functions Additional Functions Not Found in Sun Solaris 1 libc _assert used by assert macro in assert h labs srand fsetpos fgetpos atexit difftime div ldiv fpos memmove raise rand strerror strtoul Name Header Non ANSI Behavior of Sun Version _cvi_fflush stdio h Does not handle NULL argument properly _cvi_fopen stdio h Does not support binary open mode b Append open mode
89. Implements printf and scanf Although the Sun Solaris libraries provide the ANSI C family of functions for formatted input and output scanf printf and others LabWindows CVI provides special versions of these functions for the following reasons The LabWindows CVI versions of these functions provide run time error checking not available with Sun Solaris versions The Sun Solaris 1 version of these functions do not comply fully with the ANSI C standard The Sun Solaris versions of these functions do not work with the LabWindows CVI implementation of the long double data type For standalone executables these functions come in a separate static library libcviprintf a in the lib subdirectory of the LabWindows CVI installation directory When you create an executable in LabWindows CVI LabWindows CVI links your program to this static library Main Function Must Call InitCVIRTE If your program calls any functions from the LabWindows CVI libraries you must call InitCVIRTE to initialize the libraries from the executable This function takes three arguments The first and third arguments to this function must always be 0 for UNIX applications The second must be the same value as the second parameter of your main function InitCVIRTE returns 0 if it fails You do not have to call InitCVIRTE when you run your program in the LabWindows CVI development environment because LabWindows CVI always initializes the libraries However
90. Include Paths command in the Options menu of the Project window 00ProRef book 06chap04 fm Page 24 Monday March 9 1998 3 23 PM National Instruments Corporation 5 1 LabWindows CVI Programmer Reference Manual 5 UNIX Compiler Linker Issues This chapter describes the kinds of compiled modules available under LabWindows CVI for UNIX and includes programming guidelines for modules you generate with external compilers Calling Sun C Library Functions You can call functions in the Sun Solaris C libraries from source code in LabWindows CVI LabWindows CVI automatically links your program to the following static libraries located in the usr lib directory when you build the project Solaris 1 libm a libc a Solaris 2 libsocket a libnsl a libintl a libm a libc a When you create a standalone executable LabWindows CVI invokes the Sun Solaris link editor ld to link your program to the LabWindows CVI dynamic library and to the system libraries By default the Sun Solaris link editor uses the dynamic versions of the libraries LabWindows CVI passes the following linking options to the Sun Solaris link editor Solaris 1 lm ldl lc Solaris 2 lsocket lnsl lintl lm lthread lc In general you can use the header files that Sun provides for these libraries in the usr include directory For the ANSI C functions however use the header files that come with LabWindows CVI Restrictions on Calling Sun C Library Functio
91. Issues The 4s option causes the stack based calling convention to be the default In LabWindows CVI under Watcom compatibility mode the default calling convention is always the stack based convention It cannot be changed The LabWindows CVI compiler accepts the __cdecl and __stdcall conventions under Watcom except that floating point and structure return values do not work in the __cdecl calling convention National Instruments recommends that you avoid using __cdecl with Watcom In the __cdecl calling convention and the Watcom stack based calling convention the calling function is responsible for cleaning up the stack Functions can have a variable number of arguments In the __stdcall calling convention the called function is responsible for cleaning up the stack Functions with a variable number of arguments do not work in __stdcall If you use the __stdcall qualifier on a function with a variable number of arguments LabWindows CVI does not honor the qualifier All compilers pass parameters and return values in the same way for __stdcall functions except for floating point and structure return values National Instruments recommends the __stdcall calling convention for all functions exported from a DLL except functions with a variable number of arguments Visual Basic and other non C Windows programs expect DLL functions to be __stdcall Import and Export Qualifiers You can use the following qualifiers in variable and function declar
92. LLs that use the LabWindows CVI Run time Engine As in the case of standalone executables you must distribute them along with the LabWindows CVI Run time Engine Location of Files on the Target Machine for Running Executables and DLLs To assure proper execution it is critical that all files associated with your executable program are in the proper directories on the target machine On the PC you specify these files in a relative directory structure in the dialog box that appears when you select Create Distribution Kit from the Build menu of the Project window in LabWindows CVI Refer to the LabWindows CVI User Manual for details This section describes the proper location of each of the files shown in Figure 7 1 00ProRef book 06chap07 fm Page 9 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 10 National Instruments Corporation LabWindows CVI Run Time Engine under Windows 95 NT Table 7 1 shows the files that comprise the LabWindows CVI Run time Engine for Windows 95 NT These files come on a separate diskette or in a separate directory in the CD ROM The LabWindows CVI installation program installs the files along with the development environment The Create Distribution Kit command in the Build menu of the Project window can bundle the Run time Engine DLLs and drivers into your distribution kit Also you can make copies of this disk
93. LabWindows CVI Programmer Reference Manual LabWindows CVI Programmer Reference Manual February 1998 Edition Part Number 320685D 01 00ProRef book 01Title fm Page 1 Monday March 9 1998 3 23 PM Internet Support E mail support natinst com FTP Site ftp natinst com Web Address http www natinst com Bulletin Board Support BBS United States 512 794 5422 BBS United Kingdom 01635 551422 BBS France 01 48 65 15 59 Fax on Demand Support 512 418 1111 Telephone Support USA Tel 512 795 8248 Fax 512 794 5678 International Offices Australia 03 9879 5166 Austria 0662 45 79 90 0 Belgium 02 757 00 20 Brazil 011 288 3336 Canada Ontario 905 785 0085 Canada Qu bec 514 694 8521 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Germany 089 741 31 30 Hong Kong 2645 3186 Israel 03 6120092 Italy 02 413091 Japan 03 5472 2970 Korea 02 596 7456 Mexico 5 520 2635 Netherlands 0348 433466 Norway 32 84 84 00 Singapore 2265886 Spain 91 640 0085 Sweden 08 730 49 70 Switzerland 056 200 51 51 Taiwan 02 377 1200 United Kingdom 01635 523545 National Instruments Corporate Headquarters 6504 Bridge Point Parkway Austin Texas 78730 5039 USA Tel 512 794 0100 Copyright 1994 1998 National Instruments Corporation All rights reserved 00ProRef book 01Title fm Page 2 Monday March 9 1998 3 23 PM Important Information Warranty The media on which you receive National Instruments software are warrante
94. Library You can add the following DLL import library files from cvi extlib to your external compiler project gpib lib GPIB GPIB 488 2 Library dataacq lib Data Acquisition Library easyio lib Easy I O for DAQ Library visa lib VISA Transition Library nivxi lib VXI Library ivi lib IVI Library cviauto lib ActiveX Automation Library If you use an instrument driver that makes references to both the GPIB and VXI libraries you can include both gpib lib and nivxi lib to resolve the references to symbols in those libraries If you do not have access to one of these files you can replace it with one of following files gpibstub obj stub GPIB functions vxistub obj stub VXI functions 00ProRef book 06chap03 fm Page 9 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 10 National Instruments Corporation If you use an external compiler that requires a WinMain entry point the following optional library allows you to define only main in your program cviwmain lib contains a WinMain function which calls main Include Files for the ANSI C Library and the LabWindows CVI Libraries The cvirt lib import library contains symbols for all the LabWindows CVI libraries except the ANSI C standard library When you create an executable or DLL in an external compiler you use the compiler
95. March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 17 LabWindows CVI Programmer Reference Manual Note For LabWindows CVI for Windows 3 1 the actual stack size approaches 64 KB when you set the Debugging level to None Include Paths The Include Paths command in the Options menu of the Project window specifies the directory search path for include files The Include Paths dialog box has two lists one for include paths specific to the project and one for paths not specific to the project When you install VXIplug amp play instrument drivers the installation program places the include files for the drivers in a specific VXIplug amp play include directory LabWindows CVI also searches that directory for include files Include Path Search Precedence LabWindows CVI searches for include files in the following locations and in the following order 1 Project list 2 Project specific include paths 3 Non project specific include paths 4 The paths listed in the Instrument Directories dialog box 5 The subdirectories under the cvi toolslib directory 6 The cvi instr directory 7 The cvi include directory 8 The cvi include ansi directory 9 The VXIplug amp play include directory 10 The cvi sdk include directory Windows 95 NT only 00ProRef book 06chap01 fm Page 17 Monday March 9 1998 3 23 PM National Instruments Corporation 2 1 LabWindows CVI Programme
96. Message Type Error Comment 00ProRef book 07AppA fm Page 27 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 28 National Instruments Corporation No data relocation section found for external module FILE Link Error External object module does not contain the relocation information necessary to link it in with the rest of the project You cannot load an executable as an object module No data section found for external module FILE Link Error External object module does not contain the initialized data necessary to link it in with the rest of the project Ensure that you built the external object file correctly No pack settings currently pushed Compile Error pack pragma used a pop when there were no pushes No symbol table found for external module FILE Link Error External object module does not contain the symbol table information necessary to link it in with the rest of the project Ensure that you built the external object file correctly No text relocation section found for external module FILE Link Error External object module does not contain the relocation information necessary to link it in with the rest of the project You cannot load a linked executable as an object module No text section found for external module FILE Link Error External object module does not contain the initialized instruction data necessary to
97. Monday March 9 1998 3 23 PM Index National Instruments Corporation I 13 LabWindows CVI Programmer Reference Manual non ANSI behavior of Sun Solaris 1 ANSI C library 5 4 printf and scanf functions under LabWindows CVI 5 4 run state change callbacks not available 5 5 static and shared versions of ANSI C and Sun libraries 5 3 to 5 4 externally compiled modules 5 6 to 5 7 compiling 5 6 to 5 7 restrictions 5 6 incompatibilities 5 10 to 5 11 between LabWindows CVI and ANSI C 5 10 to 5 11 between LabWindows CVI and Sun Solaris 5 11 locking process segments in memory using plock 5 7 shared libraries 5 2 LabWindows CVI Run time Engine as shared library 5 2 using dlopen 5 2 Solaris 1 ANSI C Library implementation 5 8 to 5 9 functions not found in Sun Solaris 1 libc 5 9 replacement functions table 5 9 UNIX operating system configuration options for Run time Engine 7 7 distribution of standalone executables 7 2 to 7 5 minimum system requirements 7 5 Solaris 1 7 4 to 7 5 Solaris 2 7 3 to 7 4 Unload command Instruments menu 2 3 UnRegisterWinMsgCallback function 4 21 useDefaultTimer option 7 7 user interface See graphical user interface GUI user interface events See events User Interface Library 9 3 user interface resource uir files accessing from running standalone executables 7 12 multiplatform application considerations 6 3 required for running standalone executables 7 9 resolvin
98. NY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prio
99. Run Time 1 12 Disabling Library Errors at Run Time 1 12 Disabling Protection for Individual Pointer 1 12 Disabling Library Protection Errors for Functions 1 13 Details of User Protection 1 14 Pointer Casting 1 14 Dynamic Memory 1 15 Avoid Unassigned Dynamic Allocation in Function Parameters 1 15 Library Functions 1 16 Unions 1 16 Stack Size 1 16 Include Paths 1 17 Include Path Search Precedence 1 17 Chapter 2 Using Loadable Compiled Modules About Loadable Compiled Modules
100. Standard 1 2 Calling Conventions Windows 95 NT Only 1 2 Import and Export Qualifiers 1 3 C Comment Markers 1 4 Duplicate Typedefs 1 4 Structure Packing Pragma Windows 3 1 and Windows 95 NT Only 1 4 Program Entry Points Windows 95 NT Only 1 5 C Library Issues 1 5 Using the Low Level I O Functions 1 5 C Data Types and 32 Bit Compiler Issues 1 6 Data Types 1 6 Converting 16 Bit Source Code to 32 Bit Source Code 1 6 Debugging Levels 1 8 User Protection 1 8 Ar
101. Supported LabWindows CVI for Windows 95 NT does not load 16 bit DLLs If you want to do this you must obtain a 32 to 16 bit thunking DLL and a 32 bit DLL import library Run State Change Callbacks in DLLs You can include run state change callbacks in DLLs you build in LabWindows CVI When running a program in LabWindows CVI a run state change callback receives notification when the program starts suspends resumes and stops If you include a run state change 00ProRef book 06chap03 fm Page 2 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 3 LabWindows CVI Programmer Reference Manual callback in a DLL you must take special care Refer to the Notification of Changes in Run State section in Chapter 2 Using Loadable Compiled Modules of this manual for a detailed discussion of run state change callbacks DllMain Each DLL can have a DllMain function except that the Borland compiler uses DllEntryPoint as the name The operating system calls the DllMain function with various messages To generate the template for a DllMain function use the Insert Constructs command in the Edit menu of a Source window Use caution when inserting code in the PROCESS_ATTACH and PROCESS_DETACH cases In particular avoid calling into other DLLs in these two cases The order in which Windows 95 NT initializes DLLs at startup and unloads them at process termination is not well defined
102. Thus the DLLs you want to call might not be in memory when your DllMain receives the PROCESS_ATTACH or PROCESS_DETACH message It is always safe to call into the LabWindows CVI Run time Engine in a run state change callback as long as you do so before calling CloseCVIRTE Releasing Resources when a DLL Unloads When a program terminates the operating system disposes resources your DLL allocates If your DLL remains loaded throughout program execution it does not need to dispose resources explicitly when the system unloads it at program termination However if the program unloads your DLL during program execution it is a good idea for your DLL to dispose of any resources it allocates It can release resources in the DllMain function in response to the PROCESS_DETACH message The DLL can also release resources in a function that it registers with the ANSI C atexit function The system calls the function you register when the DLL receives the PROCESS_DETACH message If your DLL calls into the LabWindows CVI Run time Engine DLL it can allocate resources such as user interface panels If a program unloads your DLL during execution you might want to dispose these resources by calling functions such as DisposePanel in the LabWindows CVI Run time Engine On the other hand as explained in the previous section it is generally unsafe to call into other DLLs in response to the PROCESS_DETACH message To solve this dilemma you can use the CVIRTEHasBee
103. VI Programmer Reference Manual National Instruments recommends that your installation program modify cvi ini cvi ini or the Registry automatically Under Windows 3 1 the modini program is in the LabWindows CVI bin subdirectory for this purpose A documentation file called modini doc and the source code are in the same directory Under Windows 95 NT the modreg program is in the LabWindows CVI bin subdirectory for this purpose A documentation file called modreg doc and the source code are in the same directory Assume that you install two fp files in the following locations c newlib liba fp c genlib libb fp If liba depends on libb you must add the following path to the user s Instrument Directories list c genlib For LabWindows CVI to be able to find the dependent file under Windows 3 1 and UNIX your modini command file must be add InstrumentDirectories InstrDir c genlib After the user installs the library files the modini program must be run on the user s disk using cvi ini and the command file For LabWindows CVI to be able to find the dependent file under Windows 95 NT your modreg command file must be setkey HKEY_CURRENT_USER Software National Instruments appendkey CVI latestVersion add InstrumentDirectories InstrDir c gewlib After the user installs the library files the modreg program must be run on the user s disk using the command file Caution LabWindows CVI must not be running when yo
104. VI invokes the Sun Solaris link editor ld to link your program to the shared versions of the libraries libc so and libm so Similarly when you generate a UNIX makefile by invoking the Generate Makefile command from the Build Menu of the Project window the makefile contains linker commands to use the shared versions of the libraries Thus when you run your programs as executables you use a different version of the Sun libraries including the ANSI C library than when you run them in the LabWindows CVI development environment Your program might exhibit slightly different behavior as a standalone executable than when run in the development environment 00ProRef book 06chap05 fm Page 3 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues LabWindows CVI Programmer Reference Manual 5 4 National Instruments Corporation Non ANSI Behavior of Sun Solaris 1 ANSI C Library The C library that comes with Sun Solaris 1 SunOS 4 1 x does not comply with the ANSI C standard as follows Some ANSI C functions are missing from the library Some library functions have different behavior than the ANSI standard specifies LabWindows CVI corrects these problems by adding a library libcfix a that replaces and supplements the Sun Solaris library as necessary The Solaris 1 ANSI C Library Implementation section contains more information about how LabWindows CVI provides an ANSI C library on Solaris 1 LabWindows CVI
105. Windows SDK function FPTerm to restore the previous exception handler and terminate the DLL s use of WIN87EM DLL typedef void LPFNSIGNALPROC int int prototypes for functions in WIN87EM d11 LPFNSIGNALPROC PASCAL_FPInit void VOID PASCAL_FPTerm LPFNSIGNALPROC void DllFunction void LPFNSIGNALPROC OldFPHandler save the floating point state and setup the floating point exception handler for this DLL OldFPHandler _FPInit signal SIGFPE DLLsFPEHandler optional 00ProRef book 06chap04 fm Page 6 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 7 LabWindows CVI Programmer Reference Manual perform the computations restore the floating point state _FPTerm OldFPHandler Note If you use Microsoft C to build the DLL you might get a linker error for an undefined symbol _acrtused2 This error occurs only in Microsoft C versions 7 00 and later Include the following dummy function in your DLL to fix this error Also when linking to the DLL specify WIN87EM LIB as the first library to be linked void _acrtused2 void DLL Glue Code Because LabWindows CVI is a 32 bit application it does not use 16 bit import libraries or import statements in module definition files Instead LabWindows CVI uses 32 bit DLL glue code In some cases it is sufficient to use glue code that LabW
106. You can distribute with your DLL the same include file that you include in the source files you use to make the DLL This is especially useful when you create DLLs from instrument drivers You can use the same source code to create the DLL in LabWindows CVI and any of the four compatible external compilers You can use your DLL in Microsoft Visual Basic or other non C environments Automatic Inclusion of Type Library Resource for Visual Basic The Create Dynamic Link Library command gives you the option to automatically create a Type Library resource and include it in the DLL When you use this option Visual Basic users can call the DLL without having to use a header file that contains Declare statements for the DLL functions The command requires that you have a function panel file for your DLL 00ProRef book 06chap03 fm Page 24 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 25 LabWindows CVI Programmer Reference Manual If your function panel file contains help text you can generate a Windows help file from it using the Generate Windows Help command in the Options menu of the Function Tree Editor window The Create Dynamic Link Library command provides an option to include links into the Window help file in the Type Library These links allow Visual Basic users to access the help information from the Type Library Browser Visual Basic has a more restricte
107. __________________________ _______________________________________________________________________________ If you find errors in the manual please record the page numbers and describe the errors _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ Thank you for your help Name _________________________________________________________________________ Title __________________________________________________________________________ Company _______________________________________________________________________ Address ________________________________________________________________________ _______________________________________________________________________________ E Mail Address __________________________________________________________________ Phone ___ __________________________ Fax ___ _______________________________ Mail to Technical Publications Fax to Technical Publications National Instruments Corporat
108. __________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ List any error messages ___________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ The following steps reproduce the problem ___________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ 00ProRef book 09CCApx fm Page 3 Monday March 9 1998 3 23 PM LabWindows CVI Hardware and Software Configuration Form Record the settings and revisions of your hardware and software on the line to the right of each item Complete a new copy of this form each time you revise your software or hardware configuration and use this form as a reference for your current configuration Completing this form accurately before contacting National In
109. ____________________________________________ Programming language ___________________________________________________________ Programming language version _____________________________________________________ Other boards in system ____________________________________________________________ Base I O address of other boards ____________________________________________________ DMA channels of other boards _____________________________________________________ Interrupt level of other boards ______________________________________________________ 00ProRef book 09CCApx fm Page 5 Monday March 9 1998 3 23 PM Documentation Comment Form National Instruments encourages you to comment on the documentation supplied with our products This information helps us provide quality products to meet your needs Title LabWindows CVI Programmer Reference Manual Edition Date February 1998 Part Number 320685D 01 Please comment on the completeness clarity and organization of the manual _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _____________________________________________________
110. a limited version 00ProRef book 06chap05 fm Page 10 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues National Instruments Corporation 5 11 LabWindows CVI Programmer Reference Manual of setlocale In contrast LabWindows CVI links standalone executables to the shared library libc so which contains the fully functional version of setlocale Between LabWindows CVI and Sun Solaris The following incompatibilities exist between LabWindows CVI and Sun Solaris LabWindows CVI does not support the long long data type some header files on Solaris 2 use In LabWindows CVI you cannot use that data type or call functions that use that data type LabWindows CVI implements the data type long double as an 8 byte object in the same way that it implements double Sun Solaris implements long double as a 16 byte object As a result Sun Solaris functions that use long double do not work properly in LabWindows CVI The LabWindows CVI implementation of the printf and scanf family of functions does not support the Sun Solaris implementation of long double LabWindows CVI does not support wide character constants wchar_t of the form L ab The data types jmp_buf and sigjmp_buf that the header file setjmp h defines are different for LabWindows CVI and Sun Solaris The LabWindows CVI versions of these buffers are larger than the Sun Solaris versions because LabWindows CVI stores additional debugging in
111. abWindows CVI you might have to contact the developer of the DLL to obtain modifications Because LabWindows CVI is a 32 bit application special glue code is required to communicate with a 16 bit DLL For some DLLs LabWindows CVI can automatically generate this glue code from the include file when loading the DLL For other DLLs you have to modify the glue source code and compile it with Watcom into a obj or lib file The normal way of communicating with a DLL is by calling functions in the DLL However cases exist where you must use other communication methods The most typical case is that of an interrupt service routine in a DLL that notifies the application when an interrupt occurs This is done through a callback function Also LabWindows CVI can recognize messages posted by a DLL through the Windows Application Programming Interface API function PostMessage and initiate a callback function Helpful LabWindows CVI Options for Working with DLLs LabWindows CVI provides two options that can be helpful when working with DLLs The options can be found in the Run Options menu of the Project window Enable the Check Disk Dates Before Each Run option when you iteratively modify a DLL or DLL glue code file and run a LabWindows CVI test program that calls into the DLL By enabling the Check Disk Dates Before Each Run option you ensure that you link the most recent version of the DLL and DLL glue code into your program You can leave thi
112. ad Error LabWindows CVI encountered an unknown OMF record while loading an external object module Ensure that the external object module was compiled properly Unknown size of type TYPE Compile Error You performed pointer arithmetic on operand s that are pointers to types of unknown size The types are probably incomplete types or pointer to function types Ensure that the pointer types point to fully declared types and are not pointers to functions Unknown specifier Non Fatal Run time Error Specifier in the format specifier is not valid Unnamed pop matching named push Compile Warning pack pragma used an unnamed pop that balances a name push Unrecognized character escape sequence Compile Warning Character escape sequence does not conform to any known character escape sequence octal escape sequence or hexadecimal escape sequence Unrecognized character escape sequence CHAR Compile Warning Character escape sequence does not conform to any known character escape sequence octal escape sequence or hexadecimal escape sequence Unrecognized declaration Compile Error Declaration is unrecognizable Check the declaration syntax for the function object or type you want to use Unrecognized preprocessor directive Compile Error character begins an unknown preprocessor directive Check the spelling of the preprocessor directive Unrecognized statement Compile Error St
113. age 4 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 5 LabWindows CVI Programmer Reference Manual Assignment to const identifier NAME Compile Error const variables or parameters are read only values that you cannot modify once initialized Ensure that no assignment operations modify the identifier Assignment to const location Compile Error const variables or parameters are read only values that you cannot modify once initialized Ensure that no assignment operations modify the lvalue such as an array reference or a pointer dereference that specifies the const location Attempt to free invalid pointer expression Fatal Run time Error Pointer value you passed to the free function is invalid It is probably the result of a previous invalid pointer operation Attempt to free pointer to freed memory Fatal Run time Error Pointer value you passed to the free function refers to a location in dynamic memory that you already deallocated Attempt to free uninitialized pointer Fatal Run time Error Pointer value you passed to the free function is invalid because you did not initialize it It is probably an uninitialized local variable Initialize local variables before you use them Attempt to read beyond end of array Non Fatal Run time Error Source array is not large enough to satisfy the destination specifiers Attempt to read beyond
114. al Illegal continue statement Compile Error continue statement appears outside a loop statement Remove the continue statement Illegal default label Compile Error default label appears outside the context of a switch statement Remove the default label Illegal expression Compile Error Compiler encountered the wrong type of token while parsing an expression where it expected an identifier string literal integer constant floating constant or Illegal extern definition of NAME all interactive window variable definitions must be static Compile Error No Interactive Execution window definitions are visible outside the scope of the Interactive Execution window You cannot initialize external symbols in the Interactive Execution window Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 17 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 18 National Instruments Corporation Illegal formal parameter types Compile Error Parameter type of void appears in a function prototype declaration that has more than one argument Remove the void parameter type or change the function prototype so that it contains only the single void parameter type Illegal header name include expects FILE or lt FILE gt Compile Error Unexpected character follows an include where a heade
115. al 4 20 National Instruments Corporation int g struct x ptr int retval unsigned short cw387 char savedPointer savedPointer ptr gt name if Alloc16BitAlias ptr gt name ITEM_SIZE amp ptr gt name 1 return lt error code gt cw387 Get387CW retval int InvokeIndirectFunction __static_g ptr Set387CW cw387 Free16BitAlias ptr gt name ITEM_SIZE ptr gt name savedPointer return retval DLL Exports Functions by Ordinal Value Only If your DLL does not export its functions by name but by ordinal number only you must modify the GetProcAddress function calls in the glue code Instead of passing the name of the function as the second parameter pass PASS_WORD_AS_POINTER OrdinalNumber where OrdinalNumber is the ordinal number for the function For example if the ordinal number for the function InstallCallback is 5 change the glue code as follows Generated Glue Code if fp GetProcAddress DLLHandle InstallCallback funcname _InstallCallback goto FunctionNotFoundError Change to if fp GetProcAddress DLLHandle PASS_WORD_AS_POINTER 5 funcname _InstallCallback goto FunctionNotFoundError 00ProRef book 06chap04 fm Page 20 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 21 LabWindows CVI Programmer Reference Manual Recognizing Windows Messages Passed from a DLL The norma
116. ally control whether LabWindows CVI suspends execution when it encounters a protection error This function does not affect the Break on Library Errors feature Disabling Library Errors at Run Time The Break on Library Errors option in the Run Options command in the Options menu of the Project window lets you choose whether LabWindows CVI suspends execution when a library function returns an error code The option takes effect when you start executing the project You can override the initial setting in your program by using the SetBreakOnLibraryErrors function in the Utility Library Use of this function does not affect the reporting of other types of library protection errors Disabling Protection for Individual Pointer You can disable pointer checking for a particular pointer by casting it first to an arithmetic type and then back to its original type as shown in the following macro define DISABLE_RUNTIME_CHECKING ptr ptr void unsigned ptr char charPointer run time checking is performed for charPointer before this line DISABLE_RUNTIME_CHECKING charPointer no run time checking is performed for charPointer after this line 00ProRef book 06chap01 fm Page 12 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 13 LabWindows CVI Programmer Reference Manual This macro could be useful in the following situation LabWindows CVI reports erroneous ru
117. and decimal point do not constitute a valid number Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 36 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 37 LabWindows CVI Programmer Reference Manual Stack Overflow Fatal Run time Error Program exceeds the stack limit Change the size of the stack in the Run Options dialog box if you think that the code is executing correctly Otherwise ensure that the program does not contain any infinite recursion struct NAME declared inside parameter list has scope only for this declaration Compile Warning Structure declared in the parameter list has scope only within the parameter list As a result its type is incompatible with all other types You must declare the structure type before you declare function types that use it Structures containing unspecified size array fields must contain other fields Compile Error Structures that contain arrays with unspecified size must contain at least one other non zero size member LabWindows CVI supports these types of structures as an extension to the ANSI C standard Subtraction involving invalid pointer Non Fatal Run time Error One of the pointer expressions in the subtraction is invalid It is probably the result of a previous invalid pointer operation Subtraction involving null pointer Non F
118. and informs you It is important to remember that this feature works only when you execute source code in the LabWindows CVI development environment The string functions can write beyond the end of a string or array without detection resulting in corruption of memory Therefore you must use the Formatting and I O functions on strings and arrays with caution In addition to the return codes the GetFmtErrNdx and NumFmtdBytes functions return information on how the last scanning and formatting function executed The GetFmtIOError function returns a code that contains specific error information on the last 00ProRef book 06chap09 fm Page 6 Monday March 9 1998 3 23 PM Chapter 9 Checking for Errors in LabWindows CVI National Instruments Corporation 9 7 LabWindows CVI Programmer Reference Manual Formatting and I O Library function that performed file I O The GetFmtIOErrorString function converts this code into an error string Refer to the LabWindows CVI Standard Library Reference Manual for more information Utility Library Utility Library functions report error codes as return values You can check each individual function description in the LabWindows CVI Standard Libraries Reference Manual or in the LabWindows CVI function panel help to determine the error conditions that can occur in each function ANSI C Library Some of the ANSI C library functions report error codes as return values Some functions also set the global varia
119. andle When a function reports status through a separate function as in the RS 232 Library check for errors in a similar way In this case the status function returns a negative value when the original function fails bytesRead ComRd 1 buffer 10 if ReturnRS232Error lt 0 ErrorCheck Error Reading From ComPort 1 ReturnRS232Error GetRS232ErrorString ReturnRS232Error Notice that the above function also returns the number of bytes read from the serial port You can compare the number of bytes read to the number you request and if a discrepancy exists take the appropriate action Notice that the error codes differ between the RS 232 Library and the User Interface Library A section describing how each LabWindows CVI library reports errors follows this section 00ProRef book 06chap09 fm Page 2 Monday March 9 1998 3 23 PM Chapter 9 Checking for Errors in LabWindows CVI National Instruments Corporation 9 3 LabWindows CVI Programmer Reference Manual After your program detects an error it must take some action to either correct the situation or prompt the user to select a course of action The following example shows a simple error response function void ErrorCheck char errMsg int errVal char errString char outputMsg 256 int response Fmt outputMsg s Error d n s nContinue errMsg errVal errString response ConfirmPopup ErrorCheck outputMsg if response 0 e
120. arison involving null pointer Comparison involving invalid pointer Comparison of pointers to different objects Pointer comparison involving address of non array object Comparison of pointers to freed memory Pointer Subtraction Non Fatal LabWindows CVI generates pointer subtraction errors for erroneous pointer subtraction expressions The following user protection errors involve pointer subtraction Subtraction involving uninitialized pointer Subtraction involving null pointer Subtraction involving invalid pointer Subtraction of pointers to different objects Pointer subtraction involving address of non array object Subtraction of pointers to freed memory Pointer Casting Non Fatal LabWindows CVI generates a pointer casting error when you cast a pointer expression to type AnyType and not enough space exists for an object of type AnyType at the location the pointer expression specifies This occurs only when casting a dynamically allocated object for the first time such as with the code double malloc 1 In this example LabWindows CVI reports the following error Not enough space for casting expression to pointer to double 00ProRef book 06chap01 fm Page 10 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 11 LabWindows CVI Programmer Reference Manual Dynamic Memory Protection Errors Dynamic memor
121. atal Run time Error One of the pointer expressions in the subtraction has the value NULL Both expressions in pointer subtractions must point into the same array object Subtraction involving uninitialized pointer Non Fatal Run time Error One of the pointer expressions in the subtraction is invalid because you did not initialize it Subtraction of pointers to different objects Non Fatal Run time Error Pointer expressions in the subtraction point to two distinct objects Both expressions in pointer subtractions must point into the same array object Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 37 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 38 National Instruments Corporation Subtraction of pointers to freed memory Non Fatal Run time Error One of the pointer expressions in the subtraction is invalid because it refers to a location in dynamic memory that you deallocated with the function free Once memory is free all pointers into that block of memory are invalid Switch statement with no cases Compile Warning Switch statement contains no case or default label Symbol NAME defined in modules FILE and FILE In Borland mode multiple modules must not contain uninitialized definitions of the same global variable Borland creates a separate variable for each defini
122. ate Static Library command Note This import source code does not operate in the same way as a normal DLL import library When you link a normal DLL import library into an executable the operating system attempts to load the DLL as soon as the program starts The import source code LabWindows CVI generates does not load the DLL until you call one of the functions it exports Preparing Source Code for Use in a DLL When you create a DLL you must address the following issues that can affect your source code and include file The calling convention you use to declare the functions you want to export How you specify which DLL functions and variables you want to export Marking imported symbols in the DLL include file you distribute This section discusses how you can address these issues when you create your DLL in LabWindows CVI If you create your DLL in an external compiler the approach is very similar The external compilers however do not agree in all aspects This chapter also discusses these differences Some of the information in this section is very technical and complex Recommendations on the best approaches to these issues are at the end of the section These recommendations are intended to make creating the DLL as simple as possible and to make it easy to use the same source code in LabWindows CVI and the external compilers Calling Convention for Exported Functions If you intend for only C or C programs
123. atement syntax is unrecognizable Check the statement syntax for the type of statement you want to use Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 44 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 45 LabWindows CVI Programmer Reference Manual Unsigned operand of unary Compile Warning You performed a nonsensical unary negation operation on an unsigned type A negation operation on an unsigned type is not effective Unsupported segment combination type NUMBER segment name NAME Load Error LabWindows CVI encountered a bad segment while loading an external object module Ensure that the external object module was compiled properly Use of keyword __import contradicts previous use of keyword __export at POSITION Compile Error Use of a keyword in a variable definition contradicts a previous definition for example int __export x int __import x 0 Use of keyword __export contradicts previous use of keyword __import at POSITION Compile Error Use of a keyword in a variable definition contradicts a previous definition for example int __import x int __export x 0 Use of keyword __declspec dllimport contradicts previous use of keyword __declspec dllexport at POSITION Compile Error Use of a keyword in a variable definition contradicts a previous definition
124. ational Instruments Corporation DLLs That Can Use Glue Code Generated at Load Time If your DLL can use glue code generated at load time LabWindows CVI automatically generates the glue code based on the contents of the h file it associates with the DLL when it loads it Any functions declared as PASCAL pascal or _pascal in the DLL should be declared as PASCAL in the h file LabWindows CVI ignores the PASCAL keyword except when generating the glue code Use only standard ANSI C keywords in the h file The keyword PASCAL is the only exception to this rule For example do not use far near or huge Note You can create an object module that contains the glue code If you do so LabWindows CVI can load the DLL faster because it does not have to regenerate and recompile the glue code To create the object module load the h file into a Source window and select Options Generate DLL Glue Object If the DLL pathname is listed in the project replace it with the object module file If the DLL is not listed in the project but is associated with a fp file make sure the object module is in the same directory as the fp file DLLs That Cannot Use Glue Code Generated at Load Time If your DLL cannot use glue code generated at load time you must generate a glue code source file from the DLL include file using the Generate DLL Glue Source command from the Options menu of a Source window You must then compile the glue code using the Watcom com
125. ational Instruments Corporation 2 3 LabWindows CVI Programmer Reference Manual If the instrument driver program file is a compiled module it must adhere to the requirements outlined for each operating system in Chapter 3 Windows 95 NT Compiler Linker Issues Chapter 4 Windows 3 1 Compiler Linker Issues and Chapter 5 UNIX Compiler Linker Issues of this manual Using a Loadable Compiled Module as a User Library You can install your own libraries into the Library menu A user library has the same form as an instrument driver You can load as a user library anything that you can load into the Instrument menu provided the program is in compiled form Refer to the Using Instrument Drivers and the Instrument Menu sections of Chapter 3 Project Window of the LabWindows CVI User Manual for more information The main difference between modules you load as instrument drivers and those you load as user libraries is that you can unload instrument drivers using the Unload command in the Instrument menu but you cannot unload user libraries You cannot edit and recompile user libraries while they are loaded Install user libraries by selecting the Library Options command in the Project Options menu The next time you run LabWindows CVI the libraries load automatically and appear at the bottom of the Library menu You can develop a user library module to provide support functions for instrument drivers or any other modules in your project By installing
126. ations __declspec dllimport __declspec dllexport __import __export _import _export 00ProRef book 06chap01 fm Page 3 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 4 National Instruments Corporation At this time not all these qualifiers work in all external compilers The LabWindows CVI cvidef h include file defines the following macros which are designed to work in each external compiler DLLIMPORT DLLEXPORT An import qualifier informs the compiler that the symbol is defined in a DLL Declarations of variables imported from a DLL require import qualifiers but function declarations do not An export qualifier is relevant only in a project for which the target type is Dynamic Link Library The qualifier can be on the declaration or definition of the symbol or both The qualifier instructs the linker to include the symbol in the DLL import library C Comment Markers You can use double slashes to begin a comment The comment continues until the end of the line Duplicate Typedefs The LabWindows CVI compiler does not report an error on multiple definitions of the same typedef identifier as long as the definitions are identical Structure Packing Pragma Windows 3 1 and Windows 95 NT Only The pack pragma can be used within LabWindows CVI to specify the maximum alignment factor for elements within a structure For example assume the following
127. ayImageFile SavePanelState and RecallPanelState These functions interpret relative pathnames as being relative to the directory that contains the executable Table 7 3 Pathnames and Targets of Links Pathname of Link Target of Link usr lib libcvi so usr lib libcvi so n usr lib libcvi so n cvirte lib libcvi so n 00ProRef book 06chap07 fm Page 12 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 13 LabWindows CVI Programmer Reference Manual Rules for Using DLL Files under Windows 95 NT Under Windows 95 NT your executable or DLL can link to a DLL only through an import library This section refers to a DLL an executable or another DLL uses as a subsidiary DLL You can link an import library into your program in any of the following ways List it in your project Associate it with the fp file for an instrument driver or user library Dynamically load it by a calling LoadExternalModule If you list a DLL import library in the project or associate it with an instrument driver or user library LabWindows CVI statically links the import library into your executable or DLL On the other hand if you load the import library through a call to LoadExternalModule you must distribute it separately from your executable Refer to the Rules for Loading Files Using LoadExternalModule section later in this chapter for more informati
128. bel NAME Compile Error Case label value appears more than once in the switch statement Eliminate any duplicate case label values in the switch statement Duplicate definition for NAME previously declared at POSITION Compile Error You redeclared a previously defined parameter name eliminate one of the parameter declarations Duplicate field name NAME in TYPE Compile Error You have already declared the member name of the struct or union type Eliminate one of the member declarations from the struct or union type declaration Dynamic memory is corrupt Fatal Run time Error LabWindows CVI encountered corrupt data while allocating or freeing dynamic memory Empty declaration Compile Error or Warning You did not declare an object or type It is an error if the empty declaration appears in the context of an old style parameter declaration Elf library is out of date Object Load Error LabWindows CVI expects a more recent version of the shared library libelf so that it uses to load ELF objects As a result LabWindows CVI is unable to read or write object and library files enum NAME declared inside parameter list has scope only for this declaration Compile Warning Enumeration you declared in the parameter list has scope only within the parameter list As a result its type is incompatible with all other types You must declare the enumeration type before you declare function ty
129. bit code to 32 bit code 1 6 to 1 7 debugging levels 1 8 error messages A 1 to A 46 limits table 1 1 non ANSI C keywords 1 2 overview 1 1 user protection errors general protection errors 1 11 library protection errors 1 11 to 1 12 memory corruption fatal 1 11 memory deallocation non fatal 1 11 pointer arithmetic non fatal 1 8 to 1 9 pointer assignment non fatal 1 9 pointer casting non fatal 1 10 pointer comparison non fatal 1 10 pointer dereference errors fatal 1 9 to 1 10 pointer subtraction non fatal 1 10 Compiler Defines command Options menu 1 2 3 27 compiler options compiled object modules Borland C 4 x 4 3 Symantec C 6 0 4 3 Watcom 4 2 setting 1 2 Compiler Options command Options menu 1 2 compiler linker issues See specific operating system e g UNIX operating system configuring Run time Engine See Run time Engine configuring converting 16 bit source code to 32 bit source code 1 6 to 1 7 Create Distribution Kit command Build menu 7 1 7 9 Create Dynamic Link Library command 3 24 7 18 Create Object File command Options menu 3 26 Create Standalone Executable File command 3 20 7 16 Create Static Library command 3 21 3 26 creating loadable compiled modules See loadable compiled modules platform independent applications See multiplatform applications building standalone executables See standalone executables creating and distributing Windows DLLs See W
130. ble errno Generally the functions do not clear errno when they return successfully To learn more about these values you can consult a publication such as C A Reference Manual cited in the Related Documentation section of About This Manual Also you can use the LabWindows CVI function panel help to determine the error conditions that can occur in each function LabWindows CVI Instrument Drivers Instrument drivers from National Instruments use a standard status reporting scheme Functions report error codes as return values and you can check each function individually in the LabWindows CVI function panel help to determine the error conditions that can occur in each function Instrument drivers that comply with the VXIplug amp play standard contain two error reporting functions Prefix_error_query where Prefix is the instrument prefix allows you to query the error queue in the physical instrument If the instrument does not have an error queue Prefix_error_query returns the VI_WARN_NSUP_ERROR_QUERY warning code from the VISA Library Prefix_error_message translates the error and warning codes that the other instrument driver functions return into descriptive strings IVI instrument drivers are VXIplug amp play compliant and so contain the Prefix_error_query and Prefix_error_message functions In addition IVI instrument driver functions sometimes also provide a secondary error code or an elaboration string to give you additional information a
131. bles and DLLs section later in this chapter for more information 2 Create a directory to contain your executable program and associated files Structure the directory exactly as you want it to appear after installation Test your program by running it from that directory 3 From the directory that contains your executable program and associated files execute the makepkg shell script in the misc bin directory of the LabWindows CVI installation directory to create a distribution package The script requires the following information to build the package Abbreviated package name that can have up to nine characters in the form XYZmyapp Text name for the package Default installation base directory on the user s machine Directory to place the build package The script requests the following information which is optional Company or vendor name for the package Name and path to a copyright notice file for the package Relative path and executable name to create as a symbolic link 4 The makepkg script creates the following files and directory structure In the following paths pkgname stands for the name of your application package pkgname install copyright pkgname install postinstall pkgname install preremove pkgname pkginfo pkgname pkgmap pkgname reloc pkgname contents of application directory You can now place the pkgname directory and its contents onto your distribution media
132. book 06chap04 fm Page 18 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 19 LabWindows CVI Programmer Reference Manual cw387 Get387CW retval int InvokeIndirectFunction __static_g ptr Set387CW cw387 return retval After you make the necessary changes the code should appear as follows Assume NUM_ELEMENTS is the number of pointers in the input array Assume ITEM_SIZE is the number of bytes pointed to by each pointer If you do not know ITEM_SIZE but you know that it is 64K or less you can use 64K as ITEM_SIZE int f char ptrs int retval unsigned short cw387 int i char savedPointers NUM_ELEMENTS change the pointers to 16 bit far pointers for i 0 i lt NUM_ELEMENTS i savedPointers i ptrs i if Alloc16BitAlias ptrs i ITEM_SIZE amp ptrs i 1 failed to allocate an alias restore pointers while i ptrs i savedPointer i return lt error code gt cw387 Get387CW retval int InvokeIndirectFunction __static_f ptrs Set387CW cw387 Restore the pointers for i 0 i lt NUM_ELEMENTS i Free16BitAlias ptrs i ITEM_SIZE ptrs i savedPointers i return retval 00ProRef book 06chap04 fm Page 19 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manu
133. bout an error condition You can use Prefix_GetErrorInfo to obtain the primary error code secondary error code and the elaboration string for the first error that occurred on a particular instrument session or in the current thread since you last called Prefix_GetErrorInfo You also can use the Prefix_GetAttribute function to obtain each of these data items individually for the most recent function call on a particular instrument session 00ProRef book 06chap09 fm Page 7 Monday March 9 1998 3 23 PM National Instruments Corporation A 1 LabWindows CVI Programmer Reference Manual A Errors and Warnings This appendix contains an alphabetized list of compiler warnings compiler errors link errors DLL loading errors and external module loading errors generated by LabWindows CVI Table A 1 Error Messages Error Message Type Error Comment flag is valid only with o x e f and g specifiers Non Fatal Run time Error Ensure that you use the correct format specifier and that no extra characters exist before the format specifier elif missing constant expression Compile Error Ensure that a conditional expression follows elif on the same line if missing constant expression Compile Error Ensure that a conditional expression follows if on the same line ifdef expects an identifier Compile Error Ensure that an identifier follows ifdef on the same line ifndef expects an identifier
134. call GetExternalModuleAddr or RunExternalModule on modules that you link directly into your executable or DLL Your alternatives are as follows 1 Remove the file from the project and distribute it as a separate obj lib or dll 2 Use the Other Symbols section of the External Compiler Support dialog box in the Build menu of the Project window to create an object module that contains a table of symbols you want GetExternalModuleAddr to find If you use this method pass the empty string to LoadExternalModule as the module pathname The empty string indicates that you linked the module directly into your executable or DLL using an external compiler Using LoadExternalModule on Library and Object Files Not in the Project If you call LoadExternalModule on a library or object file not in the project you must keep the library or object file separate in your distribution When you keep an object or library file separate you can manage memory more efficiently and replace it without having to replace the executable For this reason if you call LoadExternalModule on a library or object in the project remove or exclude the file from the project before you select Create Standalone Executable File or Create Dynamic Link Library and then include it as a separate file when you use Create Distribution Kit However remember that you cannot statically reference functions defined in a separate library or object file from the executable or DLL
135. ccurs while your program is running and you have not installed a handler for it LabWindows CVI terminates the program gives you a chance to save your files and exits If SIGTERM occurs when no program is running LabWindows CVI exits immediately SIGBUS SIGFPE SIGILL and SIGSEGV These signals exist to allow for hardware exceptions Because execution cannot continue beyond the instruction that caused the exception LabWindows CVI always catches these signals If this signal occurs while your program is running LabWindows CVI reports a fatal run time error 00ProRef book 06chap05 fm Page 7 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues LabWindows CVI Programmer Reference Manual 5 8 National Instruments Corporation and suspends operation at the statement that caused the exception If this signal occurs when no program is running LabWindows CVI exits immediately You cannot use signal sigaction sigset or sigvec to make your program ignore the signals this section lists Note If your program begins to loop indefinitely you can often suspend execution by sending a signal to the LabWindows CVI process as follows 1 Use the ps command to identify the process number of LabWindows CVI 2 Send the kill SIGNAL pid command to that process For example if the LabWindows CVI process number is 3478 the command kill INT 3478 sends the SIGINT signal to LabWindows CVI When you want to suspend execution
136. clared at POSITION Compile Error Declared name conflicts with a previous declaration in the same scope and name space You have already used the name in this scope Choose another name for this declaration Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 34 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 35 LabWindows CVI Programmer Reference Manual Redefinition of label NAME previously defined at POSITION Compile Error You already used the statement label in this function A statement label must be unique within the function in which you use it Redefinition of macro NAME Compile Error Macro has already been defined with a replacement list different from the current definition The same macro definition for a name may appear in the same file more than once as long both definitions agree in name and number of parameters and their replacement lists are identical Redefinition of NAME previously defined at POSITION Compile Error You have already defined the object or function in the current scope Eliminate one of the two definitions Reference parameter expected Non Fatal Run time Error Function expected a pointer but you passed it a scalar Register declaration ignored for TYPE NAME Compile Warning register storage class conflicts with the semantics of the type declar
137. clude D_NI_sparc_ 1 c mysource c Solaris 2 cc Xc I home cvi include D_NI_sparc_ 2 c mysource c When using the GNU compiler use the nostdinc flag to disable the standard include files and the I flag to add the LabWindows CVI include directory to the search list Also you must use the ansi flag For example to compile the file mysource c using LabWindows CVI headers under Solaris 1 use the following command line gcc ansi nostdinc I home cvi include D_NI_sparc_ 1 c mysource c You might see warnings about conflicting types for the built in functions memcmp and memcpy but you can ignore them Note These examples assume that home cvi include is the LabWindows CVI header files directory The actual path depends on how you install your copy of LabWindows CVI 00ProRef book 06chap05 fm Page 6 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues National Instruments Corporation 5 7 LabWindows CVI Programmer Reference Manual You cannot use the non ANSI C Sun compiler cc because it does not recognize some ANSI C constructs in the header files such as function prototypes and the keywords const void and volatile Locking Process Segments into Memory Using plock You can use the UNIX function plock to lock the text and data segments of your program into memory However this function locks all segments of the LabWindows CVI process not just the segments associated with your program Also because t
138. compiler at a time This manual refers to the compiler with which your copy of LabWindows CVI is currently compatible as the current compatible compiler 00ProRef book 06chap03 fm Page 4 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 5 LabWindows CVI Programmer Reference Manual Choosing Your Compatible Compiler When installing LabWindows CVI you must choose your compatible compiler If you want to change your choice of compatible compiler later you can run the installation program and change to another compatible compiler You can see which compatible compiler is active in LabWindows CVI by selecting the Compiler Options command in the Options menu of the Project window Object Files Library Files and DLL Import Libraries If you create an object file library file or DLL import library in LabWindows CVI you can use the file only in the current compatible compiler or in a copy of LabWindows CVI that you installed with the same compatibility choice For detailed information on using LabWindows CVI generated object and static library files in external compilers refer to the Using LabWindows CVI Libraries in External Compilers section later in this chapter If you load an object file library file or DLL import library file in LabWindows CVI you must have created the file in the current compatible compiler or in a copy of LabWindows CVI that you installed with th
139. ction call Array argument too small NUMBER bytes Argument must contain at least NUMBER bytes NUMBER elements Fatal Run time Error Library function requires an array that is larger than the specified argument Make sure you declare or allocate the array with the number of elements this error message reports Array index NUMBER too large maximum NUMBER Non Fatal Run time Error You indexed an array past the last element Assertion error EXPRESSION Fatal Run time Error Value of the argument EXPRESSION to the Standard C Library macro assert is 0 Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 3 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 4 National Instruments Corporation Assignment between TYPE and TYPE is compiler dependent Compile Warning Although allowed use caution because an assignment of an integer type expression value to an enum type target might not correspond to any known enumeration constant for that enum type Depending on the enumeration the size of the enum type can be 1 2 or 4 bytes and therefore may be incapable of representing all integer values Assignment of invalid pointer value Non Fatal Run time Error Value you assigned to a pointer is an invalid pointer value Check the right side of the assignment to determine if it is the res
140. ctory for this purpose A documentation file called modini doc and the source code are in the same directory Under Windows 95 NT the modreg program is in the LabWindows CVI bin subdirectory for this purpose A documentation file called modreg doc and the source code are in the same directory Assume that you install function panels for two libraries in the following location c newlib lib1 fp c newlib lib2 fp 00ProRef book 06chap08 fm Page 1 Monday March 9 1998 3 23 PM Chapter 8 Distributing Libraries and Function Panels LabWindows CVI Programmer Reference Manual 8 2 National Instruments Corporation To add the libraries to the user s Library menu under Windows 3 1 and UNIX your modini command file must be add Libraries LibraryFPFile c newlib lib1 fp add Libraries LibraryFPFile c newlib lib2 fp After the user installs the library files the modini program must be run on the user s disk using cvi ini and the command file To add the libraries to the user s Library menu under Windows 95 NT your modreg command file must be setkey HKEY_CURRENT_USER Software National Instruments appendkey CVI latestVersion add Libraries LibraryFPFile c newlib lib1 fp add Libraries LibraryFPFile c newlib lib2 fp After the user installs the library files the modreg program must be run on the user s disk using the command file Caution LabWindows CVI must not be running when you use the modini or modreg prog
141. d not to fail to execute programming instructions due to defects in materials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this manual is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS A
142. d of the correct size to pad the set of contiguous bit fields so that they fit exactly into a 4 byte element Example typedef struct int a 1 int b 1 int c 1 int dummy 29 pad to 32 bits MyStruct 00ProRef book 06chap03 fm Page 6 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 7 LabWindows CVI Programmer Reference Manual Returning Floats and Doubles The compilers return float and double scalar values using different mechanisms This is true of all calling conventions including __stdcall The only solution for this problem is to change your DLL API so that it uses output parameters instead of return values for double and float scalars Returning Structures For functions you do not declare with the __stdcall calling convention the compilers return structures using different mechanisms For functions you declare with __stdcall the compilers return structures in the same way except for 8 byte structures National Instruments recommends that your DLL API use structure output parameters instead of structure return values Enum Sizes By default Watcom uses the smallest integer size necessary to represent the largest enum value 1 byte 2 bytes or 4 bytes The other compilers always use 4 bytes Force compatibility by using the ei Force Enums to Type Int option with the Watcom compiler Long Doubles In Borland C C long double values are 1
143. d set of types than C Also the Create Dynamic Link Library command imposes certain requirements on the declaration of the DLL API Use the following guidelines to ensure that Visual Basic can use your DLL Always use typedefs for structure parameters and union parameters Do not use enum parameters Do not use structures that require forward references or that contain pointers Do not use pointer types except for reference parameters Creating Static Libraries in LabWindows CVI You can create static library lib files in LabWindows CVI for Windows 95 NT Static libraries are libraries in the traditional sense a collection of object files as opposed to a dynamic link library or an import library You can use just one project to create static library files that work with all four compatible external compilers but only if you include no object or library files in the project You must have a separate project for each static library you want to create Select Static Library from the submenu attached to the Target command in the Build menu of the Project window When you select the Static Library option the Create Static Library command appears below the Target command in the Build menu Refer to Chapter 4 Source Interactive Execution and Standard Input Output Windows of the LabWindows CVI User Manual for detailed information on the Create Static Library command Note If you include a lib file in a static librar
144. declaration Link Error Variable that you have declared as extern is defined in a DLL import library but you did not include the declspec dllimport qualifier in the declaration Case label must be a constant integer expression Compile Error Case labels must be known integer values at compile time make sure the case label conforms to the requirements for a constant integer expression Cast from TYPE to TYPE is illegal in constant expressions Compile Error You cannot cast a pointer type to arithmetic type in a constant expression Cast from TYPE to TYPE is illegal Compiler Error ANSI C does not allow a cast between the two types COFF Name too long Object Load Error COFF object or library you are loading contains a symbol name that is longer than the maximum legal length Comparison involving null pointer Non Fatal Run time Error One of the pointer expressions in the comparison has the value NULL Both expressions in pointer comparisons must point into the same array object Comparison involving uninitialized pointer Non Fatal Run time Error One of the pointer expressions in the comparison is invalid because you did not initialize it Comparison of pointers to different objects Non Fatal Run time Error Pointer expressions in the comparison point to two distinct objects Both expressions in pointer comparisons must point into the same array object Comparison of pointers
145. declared at POSITION Compile Error Current declaration of the identifier is inconsistent with a previous declaration of the same identifier with regard to linkage Ensure that all declarations of the identifier that you intend to be static do not conflict with declarations without the static keyword in the same scope Inconsistent type declarations for external symbol NAME in modules FILE1 and FILE2 Link Error You declared two or more external symbols with the same name but not the same type Check each program file that contains an external declaration of the symbol for type consistency Initializer exceeds bit field width Compile Warning Number of bits necessary to represent the initialization value of a bit field exceeds its declared width The compiler truncates the initialization value to fit the bit field The initialization value must be smaller or the bit field declaration must be wider Initializer must be constant Compile Error Initializer must be an expression that conforms to the semantics for a constant expression Insufficient number of arguments to FUNCTION Compile Error Function expects more arguments than you passed to it Check the function declaration for the number of parameters to the function Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 21 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWin
146. development system Using Windows SDK Functions to Create Multiple Threads Although you can use the Windows SDK Functions to create multiple threads in a LabWindows CVI program the LabWindows CVI development environment cannot handle multiple threads For instance if your main program terminates without destroying the threads they do not terminate Also the LabWindows CVI libraries are not multithread safe when you run a program in the LabWindows CVI development environment For information on using the LabWindows CVI libraries in a multithreaded executable refer to the Multithreading and the LabWindows CVI Libraries section earlier in this chapter Automatic Loading of SDK Import Libraries All the SDK functions are in DLLs LabWindows CVI and the four external compilers each come with a number of DLL import libraries for the SDK functions Most of the commonly used SDK functions are in the following three import libraries kernel32 lib gdi32 lib user32 lib LabWindows CVI for Windows 95 NT automatically loads these three libraries when it starts up and searches them to resolve references at link time Thus you do not have to include these libraries in your project 00ProRef book 06chap03 fm Page 27 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 28 National Instruments Corporation If the LabWindows CVI linker reports SDK functions as unresolved
147. distribution kit The only exceptions are DLLs for National Instruments hardware and DLLs that you load using LoadExternalModule 00ProRef book 06chap07 fm Page 13 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 14 National Instruments Corporation Do not include DLLs for National Instruments hardware in your distribution kit The user must install these DLLs from the distribution disks that National Instruments supplies If you use LoadExternalModule to load DLLs refer to the following section Rules for Loading Files Using LoadExternalModule If you use a DLL file a DLL path file or a DLL glue object module in your project or as an instrument driver the Run time Engine always looks for a corresponding DLL path pth file before it looks for the DLL itself This search mechanism lets the user of your executable place the DLLs anywhere on the target computer The Run time Engine uses the following DLL search method 1 Look for a pth file in the directory of the executable The pth file must have the same base name as the file in the project or as the instrument driver If the pth file contains an absolute path to the DLL use that path to find the DLL If the pth file contains a simple filename use the standard Windows DLL search algorithm directory of executables current working directory windows windows system then the PAT
148. dows CVI Programmer Reference Manual A 22 National Instruments Corporation Insufficient system memory for Interactive Window Link Error There is not enough memory to run the code in the Interactive Execution window Insufficient system memory for project Link Error There is not enough memory to link the project Insufficient user data memory for project Link Error There is not enough memory to link the project Invalid hexadecimal constant Compile Error A token the compiler assumes to be a hexadecimal constant is badly formed Ensure that token conforms to the syntax for hexadecimal constants especially that a valid hexadecimal digit follows the 0x or 0X prefix Invalid initialization type found TYPE expected TYPE Compile Error Expression that initializes the object declaration is type incompatible with the object Ensure that the initialization expression is assignment compatible with the object type Ensure that all constituent values of an aggregate expression match the corresponding positional types of the aggregate type such as member types of a struct or union type Invalid octal constant Compile Error A token the compiler assumes to be an octal constant is badly formed Ensure that the token conforms to syntax for octal constants especially that a valid octal digit follows the leading 0 prefix Invalid operand of unary amp NAME is declared register Compile Error It
149. ds in front of every function you export from the DLL You can make the compiler export a function by inserting _export between the return type and the function name adding the function name to the exports section of the def file or setting the option 16 bit Compiler Entry Exit Code Windows DLL all functions exportable If you add the function name to the exports section of the def file remember to convert the name to all caps if you use the PASCAL calling convention or pre append an underscore if you use the CDECL calling convention Also set the Generate Underscores option in Compiler Compiler Output Turn off the Allocate Enums as Ints option in Compiler Code Generation Set the Data Alignment options to Byte in 16 bit Compiler Processor Turn off the Case Sensitive Link and Case Sensitive Exports and Imports options in the Linker General Do not use the Linker Goodies options in Linker 16 bit Linker 00ProRef book 06chap04 fm Page 22 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 23 LabWindows CVI Programmer Reference Manual DLL Search Precedence LabWindows CVI finds a DLL file in the following ways for Windows 3 1 If the dll file is associated with a fp file LabWindows CVI uses the following search precedence to find the DLL 1 If a pth file with the same full path name as the fp file is in the pro
150. dules Ensure that the external object module was compiled with a 32 bit compiler signed type mismatch between TYPE and TYPE Compile Warning This warning is issued when the signs of the lvalue and rvalue expressions in a pointer assignment operation do not agree Both lvalue and rvalue are pointers to integer types but they point to integer types of differing signs which might cause problems if you later dereference the lvalue This diagnostic is issued if you select the Enable Signed Unsigned Pointer Mismatch Warning compiler option Simple Array conflict with format specifier Non Fatal Run time Error Array you passed to the function matches to a format specifier for a scalar or a scalar you passed to the function matches to a format specifier for an array Size of array of TYPE exceeds SIZE bytes Compile Error Size of the array or struct union type exceeds the compiler limitation of INT_MAX bytes Size of TYPE exceeds SIZE bytes Compile Error Size of the array or struct union type exceeds the compiler limitation of INT_MAX bytes sizeof applied to a bit field Compile Error Do not use the sizeof operation on a bit field Specified width is too small to read the number Non Fatal Run time Error Width you specified for a format specifier was not large enough to contain a complete number Example you specify a width of 2 for a float and the number is 02 the negative sign
151. e Error Make sure that the size you specified for the bit field is 0 and 32 NUMBER line s truncated File set to read only Compile Error Occurs when reading in source or include file Lines are limited to 254 characters where tabs count as 1 Use the editor in which you created the file to split the line Number of arguments exceed the maximum supported Non Fatal Run time Error Number of arguments exceeds the maximum that the formatting functions support Number of points is too large for current waveform buffer Fatal Run time Error Message appears when the numberofPoints parameter of a data acquisition waveform generation function is larger than the numberofPoints parameter to the function which set up the waveform buffer Object module contains unsupported FAR pointers Object Load Error External object module contains FAR pointers which you cannot implement in LabWindows CVI One of the arguments to FUNCTION has an unsupported size Glue Code Generation Error One of the function arguments has a type that the LabWindows CVI glue code generation and DLL loader do not support Only object modules produced by WATCOM C 386 fully supported Link Error External object module contains OMF records that LabWindows CVI does not recognize or support Ensure that the object file was compiled with a Watcom C 386 compiler with the recommended options Table A 1 Error Messages C
152. e Fax Australia 03 9879 5166 03 9879 6277 Austria 0662 45 79 90 0 0662 45 79 90 19 Belgium 02 757 00 20 02 757 03 11 Brazil 011 288 3336 011 288 8528 Canada Ontario 905 785 0085 905 785 0086 Canada Quebec 514 694 8521 514 694 4399 Denmark 45 76 26 00 45 76 26 02 Finland 09 725 725 11 09 725 725 55 France 01 48 14 24 24 01 48 14 24 14 Germany 089 741 31 30 089 714 60 35 Hong Kong 2645 3186 2686 8505 Israel 03 6120092 03 6120095 Italy 02 413091 02 41309215 Japan 03 5472 2970 03 5472 2977 Korea 02 596 7456 02 596 7455 Mexico 5 520 2635 5 520 3282 Netherlands 0348 433466 0348 430673 Norway 32 84 84 00 32 84 86 00 Singapore 2265886 2265887 Spain 91 640 0085 91 640 0533 Sweden 08 730 49 70 08 730 43 70 Switzerland 056 200 51 51 056 200 51 55 Taiwan 02 377 1200 02 737 4644 United Kingdom 01635 523545 01635 523154 United States 512 795 8248 512 794 5678 00ProRef book 09CCApx fm Page 2 Monday March 9 1998 3 23 PM Technical Support Form Photocopy this form and update it each time you make changes to your software or hardware and use the completed copy of this form as a reference for your current configuration Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently If you are using any National Instruments hardware or software products related to this problem include the config
153. e DLLs and the low level support driver Under Windows 3 1 the Run time Engine is an execute only version of the LabWindows CVI environment Under Sun Solaris the Run time Engine is a shared library UIR files The User Interface Resource files that your application program uses Use LoadPanel and LoadMenuBar to load these files Image files The graphical image files that you programmatically load and display on your user interface using DisplayImageFile State files The user interface panel state files that you save using SavePanelState and load using RecallPanelState DLL files Windows Only the Windows Dynamic Link Library files that your application program uses PTH files Windows 3 1 Only specify the location of DLL files when you want to load the DLL from a special directory or indicate that you want to find a DLL using the standard Windows DLL search algorithm External lib or a files Compiled 32 bit lib files on the PC or a files under UNIX that you load using LoadExternalModule and that you have not listed in the project External obj or o files Compiled 32 bit obj files on the PC or o files under UNIX that you load using LoadExternalModule and that you have not listed in the project Other files Files your executable opens using open fopen OpenFile and so on Necessary Files for Using DLLs Created in Windows 95 NT Under Windows 95 NT you can distribute D
154. e also standalone executables creating and distributing configuring 7 5 to 7 7 cvidir option 7 7 cvirtx option 7 6 DSTRules 7 7 option descriptions 7 6 setting configuration options 7 6 Solaris 1 patches required 7 5 to 7 6 UNIX options 7 7 useDefaultTimer 7 7 files required for running executable programs 7 8 to 7 9 location and type of files 7 9 to 7 11 Windows 3 1 7 11 to 7 12 Windows 95 NT 7 10 to 7 11 overview 7 1 shared library capability 5 2 system requirements Windows 3 1 7 2 Windows 95 NT 7 1 to 7 2 translating message file 7 5 S scanf function LabWindows CVI implementation 5 4 using with external compiler 3 10 SDK functions See Windows SDK functions search precedence of Windows DLLs 4 23 to 4 24 shared libraries under UNIX 5 2 shortcut keys multiplatform application considerations 6 3 SIGBUS signal 5 7 SIGFPE signal 5 7 SIGILL signal 5 7 SIGINT signal 5 7 SIGPIPE signal 5 7 SIGPOLL SIGIO signal 5 7 SIGQUIT signal 5 7 SIGSEGV signal 5 7 SIGTERM signal 5 7 Solaris See Sun Solaris source files converting 16 bit source code to 32 bit source code 1 6 to 1 7 loading with LoadExternalModule 7 18 preparing for use in Windows 32 bit DLL 3 21 to 3 24 calling conventions for exported functions 3 21 to 3 22 exporting DLL functions and variables 3 22 export qualifier method 3 22 to 3 23 include file method 3 22 00ProRef book 11Index fm Page 10 Monday March 9 1998 3
155. e base name as the DLL glue object module 3 Otherwise use the standard Windows DLL search algorithm Note Before searching for a dll file a standalone executable always looks for a pth file Therefore your choice of whether to use a pth file when you develop your application in the LabWindows CVI environment does not restrict your choice of whether to use to pth file in the standalone application Using LoadExternalModule on Source Files c If you pass the name of a source file to LoadExternalModule the source file must be in the project LabWindows CVI automatically compiles the source file and links it into the executable when you select Create Standalone Executable File or Create Dynamic Link Library For this reason you must pass a simple filename to LoadExternalModule If you use an external compiler refer to the Using LoadExternalModule on Files in the Project section earlier in this chapter If the source file is an instrument driver program that is not in the project and you link in LabWindows CVI you have two alternatives Add the instrument driver c source to the project Refer to one of the variables or functions it exports in one of your project files If the source file is an instrument program that is not in the project and you link in an external compiler you must create an object file and keep it separate from the executable 00ProRef book 06chap07 fm Page 18 Monday March 9 1998 3 23 PM
156. e executable LabWindows CVI includes in the executable only modules that your project refers to directly If an external module refers to modules not included in the executable calls to RunExternalModule or GetExternalModuleAddr on that external module fail To avoid this problem you must force any missing modules into your executable or DLL You can do this when you create your executable or DLL by using the Add Files To Executable or Add Files To DLL button to display a list of project lib project a Instrument and Library files Select the files you want to include in your executable or DLL If you select a lib or a file it is linked in its entirety Alternatively you can link modules into your executable or DLL by including dummy references to them in your program For instance if your external module references the functions FuncX and FuncY include the following statement in your program void dummyRefs void FuncX void FuncY Using LoadExternalModule on Files in the Project You can call LoadExternalModule on files listed in the project You must pass the simple filename to LoadExternalModule However when you create an executable or DLL from your project you might have additional work to do If you link your executable or DLL in LabWindows CVI the following rules apply for files listed in the project For c or obj files everything works automatically For dll or pth files Windows 3 1 o
157. e is missing from the object declaration Ensure that an identifier follows the object type specifier Missing label in goto Compile Error goto statement is missing an identifier label Missing parameter name to function FUNCTION Compile Error Parameter list of the function definition is missing an identifier for one of its parameter declarations All parameter declarations for a function definition must include an identifier except for the special case of a parameter list consisting of a single parameter of type void in which there must not be an identifier Missing parameter type Compile Error Type specifier is missing from a parameter declaration in a new style prototype function declaration Ensure that the function declaration is not mixing old style parameter declarations with new style prototype declarations Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 26 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 27 LabWindows CVI Programmer Reference Manual Missing prototype Compile Error Function declaration or call is for a function without prototype declaration information The compiler issues the diagnostic if the Require Function Prototypes compiler option is enabled Missing return value Fatal Run time Error Function does not return a value although you declared it with a r
158. e same compatibility choice If you have a DLL but you do not have a compatible DLL import library LabWindows CVI reports an error when you attempt to link your project To create a compatible import library you must have an include file that contains the declarations of all the functions and global variables you want to access from the DLL Load the include file into a Source window and select the Generate DLL Import Library command in the Options menu Make sure the calling conventions of the function declarations in the include file match the calling convention of the functions in the DLL Whereas DLLs usually export functions with the __stdcall calling convention the __stdcall keyword is sometimes missing from the function declarations in the associated include files If you generate an import library from an include file that does not agree with the calling convention the DLL uses you can successfully build a project that contains the import library but LabWindows CVI usually reports a general protection fault when you run the project Compatibility Issues in DLLs In general you can use a DLL without regard to the compiler you used to create it Only the DLL import library must be created for the current compatible compiler Some cases exist however in which you cannot call a DLL that you created using one compiler from an executable or DLL that you created using another compiler If you want to create DLLs that you can use in differen
159. e standard Windows DLL search algorithm LabWindows CVI makes an exception to facilitate using VXIplug amp play instrument driver DLLs When you install a VXIplug amp play instrument driver the installation program does not place the DLL import library in the same directory as the fp file If a fp file is in the VXIplug amp play directory LabWindows CVI searches for an import library in the VXIplug amp play library directory before it looks for a program file in the directory of the fp file unless you list the program file in the project Using The LoadExternalModule Function When you use the LoadExternalModule function to load a DLL at run time you must specify the pathname of the DLL import library not the name of the DLL Link Errors when Using DLL Import Libraries A DLL import library must not contain any references to symbols that the DLL does not export If it does LabWindows CVI reports a link error If you load the DLL using LoadExternalModule the GetExternalModuleAddr function reports an undefined references 5 error You can solve this problem by using LabWindows CVI to generate an import library Refer to the Generating an Import Library discussion later in this section DLL Path pth Files Not Supported The DLL import library contains the filename of the DLL LabWindows CVI uses the standard Windows DLL search algorithm to find the DLL Thus DLL path pth files do not work under Windows 95 NT 16 Bit DLLs Not
160. ecific to one function Libraries that have a common set of codes have a listing at the end of the chapter or manual they appear in You can find the error message for each integer value there In addition each of these libraries contains a function you can call to translate the integer value to an error string When an error code is specific to a function you can find a description for it in the function description in the LabWindows CVI manual set The error description also appears in the online help of the library function panels in LabWindows CVI Error Checking LabWindows CVI functions return status codes in one of two ways either by a function return value or by updating a global variable In some cases LabWindows CVI uses both of these methods In either case it is a good idea to monitor these values so that you can detect an error and take appropriate action A common technique for error checking is to monitor the status of functions and when a function reports an error pause the program and report the error to the user through a pop up message For example LoadPanel returns a positive integer when it successfully loads a user interface panel into memory However if a problem occurs the return value is negative The following example shows an error message handler for LoadPanel panelHandle LoadPanel 0 main uir PANEL if panelHandle lt 0 ErrorCheck Error Loading Main Panel panelHandle GetUILErrorString panelH
161. ed for the object If you declared the object to be of an array struct or union type or you qualified it as volatile remove the register keyword from the declaration Register declaration ignored for TYPE parameter Compile Warning register storage class conflicts with the semantics of the type you declared for the parameter prototype If you declared the object to be of struct or union type or you qualified it as volatile remove the register keyword from the prototype parameter declaration Repeat value not valid with s l format specifiers Non Fatal Run time Error You cannot use a repeat value with the s and l format specifiers Result of unsigned comparison is constant Compile Warning Result of lt UNSIGNED INTEGER always evaluates to 1 Table A 1 Error Messages Continued Error Message Type Error Comment EXPRESSION gt 0 00ProRef book 07AppA fm Page 35 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 36 National Instruments Corporation Segment must be of class CODE DATA BSS or STACK segment name NAME Load Error External object module contains an unknown segment class Object modules must not contain any specially named segments Segment must be USE32 segment name NAME Link Error External object module you loaded contains unsupported 16 bit segments LabWindows CVI supports only 32 bit object mo
162. ehavior as user protection errors When you set the debugging level to Standard or Extended LabWindows CVI maintains extra information for arrays structures and pointers and uses the information at run time to determine the validity of addresses Two groups of user protection errors exist based upon two characteristics severity level and error category In each case the ANSI C standard states that programs with these errors have undefined behavior The two severity levels are as follows Non Fatal errors include expressions that are likely to cause problems but do not directly affect program execution Examples include bad pointer arithmetic attempts to free pointers more than once and comparisons of pointers to different array objects The expression is invalid and its behavior is undefined but execution can continue Fatal errors include expressions that LabWindows CVI cannot execute without causing major problems such as causing a general protection fault For example dereferencing an invalid pointer value is a fatal error Error categories include pointer protection dynamic memory protection library protection and general protection errors Each of these categories includes subgroups as described in the following sections Array Indexing and Pointer Protection Errors The pointer protection errors catch invalid operations with pointers and arrays In this section these errors are grouped by the type of expression tha
163. emental Linker 3 17 00ProRef book 00ProRefTOC fm Page vii Monday March 9 1998 3 23 PM Contents LabWindows CVI Programmer Reference Manual viii National Instruments Corporation Borland C Builder 3 17 Watcom Pull in References 3 17 Creating Object and Library Files in External Compilers for Use in LabWindows CVI 3 18 Microsoft Visual C C 3 18 Borland C C 3 18 Watcom C C 3 19 Symantec C C 3 19 Creating Executables in LabWindows CVI 3 20 Creating DLLs in LabWindows CVI 3 20 Customizing an Import Library 3 20 Prepa
164. ent drivers definition 2 2 status reporting 9 7 using loadable compiled modules as program files 2 2 Instrument menu 2 3 7 15 interrupts under Windows 95 NT 3 29 IVI Library 9 5 K keywords non ANSI LabWindows CVI 1 2 L LabWindows CVI compiler See compiler LabWindows CVI Run time Engine See Run time Engine lib files See library files libraries C library issues 1 5 creating static libraries 3 25 distributing 8 1 to 8 3 adding to user s Library menu 8 1 to 8 2 specifying library dependencies 8 2 to 8 3 loading library files for standalone executables 7 16 portability issues for multiplatform applications 6 1 to 6 2 using loadable compiled modules as user libraries 2 3 Windows 95 NT compiler issues calling InitCVIRTE and CloseCVIRTE 3 14 to 3 15 include files for ANSI C library and LabWindows CVI libraries 3 10 multithreading and LabWindows CVI libraries 3 8 resolving callback references from uir files 3 10 to 3 12 resolving references from modules loaded at run time 3 12 standard input output windows 3 10 using LabWindows CVI libraries in external compilers 3 9 to 3 15 00ProRef book 11Index fm Page 6 Monday March 9 1998 3 23 PM Index National Instruments Corporation I 7 LabWindows CVI Programmer Reference Manual library files compatibility with external compilers Windows 95 NT 3 5 creating in external compilers for use in LabWindows CVI 3 18 to 3 19 loading with Load
165. er keywords 1 2 using low level I O functions 1 5 array indexing errors See pointer protection errors array passing in glue code 4 9 to 4 11 asynchronous callbacks compiled modules using 2 7 asynchronous DLL functions 4 11 to 4 12 asynchronous signal handling UNIX 5 7 to 5 8 00ProRef book 11Index fm Page 1 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 2 National Instruments Corporation B bit fields Windows 32 bit DLLs 3 6 Borland C C Borland or Symantec 32 bit compiled modules under Windows 4 2 to 4 3 Builder not supported by LabWindows CVI object or static library files 3 17 creating 16 bit Windows DLLs 4 22 creating object and library files 3 18 default library directives 3 16 static versus dynamic C libraries 3 17 turning off incremental linker 3 17 Break on Library Errors option 1 12 7 19 9 1 buffer retention by DLL glue code 4 11 to 4 12 Build menu Create Distribution Kit command 7 1 7 9 External Compiler Support command 3 11 3 13 Target command 3 20 3 21 3 25 building platform independent applications See multiplatform applications building bulletin board support B 1 C c files See source files C language extensions calling conventions Windows 95 NT 1 2 to 1 3 C style comment markers 1 4 duplicate typedefs 1 4 import and export qualifiers 1 3 to 1 4 non ANSI C standard keywords 1 2 program entry points Windows 1 5 str
166. erefore functions that return these types cannot be called from CVI if they are defined in Borland or vice versa The exceptions are the ANSI C library functions that return doubles which you can call from within Borland compiled modules Note This rule applies only to return values You can use structs floats and doubles as output parameters without limitation 00ProRef book 06chap04 fm Page 2 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 3 LabWindows CVI Programmer Reference Manual ANSI C library functions div and ldiv return structures and hence you cannot call them from Borland compiled modules The type long double is the same as double in CVI while in Borland it is 10 bytes long so you cannot share objects of this type between Borland and CVI modules This affects the Le Lf Lg format specifiers of printf sprintf fprintf scanf sscanf fscanf and others Because you cannot share structures with bit fields between Borland and CVI you cannot use the macros in stdio h getc putc fgetc fputc in Borland objects wchar_t is defined as a char in CVI whereas it is defined as a short in Borland so ANSI C library functions that return wchar_t or take wchar_t parameters do not work Use the following options when you compile with Borland C 4 x Set the target to be a Win32 application Define _NI_mswin16_
167. ers are present the b modifier must precede the o modifier Bad BSS section encountered while reading external module FILE Object Load Error Object module is corrupted or is of a type that you cannot load into LabWindows CVI Bad COFF Library header Object Load Error Library file you are loading is either corrupted or not in the COFF format Bad COFF Library member header Object Load Error COFF library you are loading contains a module that is corrupted or in an invalid format Bad location code OMF record position NUMBER OMF record type NAME Link Error Object module is corrupted or is of a type that you cannot load into LabWindows CVI Bad magic number encountered while reading external module FILE Link Error Object module is corrupted or is of a type that you cannot load into LabWindows CVI Bad method OMF record position NUMBER OMF record type NAME Link Error Object module is corrupted or is of a type that you cannot load into LabWindows CVI Bad name OMF record position NUMBER OMF record type NAME Link Error Object module is corrupted or is of a type that you cannot load into LabWindows CVI Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 6 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 7 LabWindows CVI Programmer Reference Manual Bad OMF record at po
168. es Calling Sun C Library Functions 5 1 Restrictions on Calling Sun C Library Functions 5 1 Using Shared Libraries in LabWindows CVI 5 2 Using dlopen 5 2 The LabWindows CVI Run Time Engine as a Shared Library 5 2 Creating Executables that Use the LabWindows CVI Libraries 5 3 Compatible External Compilers 5 3 Static and Shared Versions of the ANSI C and Other Sun Libraries 5 3 Non ANSI Behavior of Sun Solaris 1 ANSI C Library 5 4 LabWindows CVI Implements printf and scanf 5 4 Main Function Must Call InitCVIRTE 5 4 Run State Change Callbacks Are Not Available in Executables 5 5 Using Externally Compiled Modules 5 6 Restrictions on Externally Compiled Modules 5 6 Compiling Modules With External Compilers
169. esult of previous illegal pointer arithmetic Out of bounds pointer arithmetic NUMBER bytes NUMBER elements before start of array Non Fatal Run time Error Pointer arithmetic expression is invalid because the resulting value refers to a location before the start of an array The error message shows the number of bytes and number of array elements before the beginning of the array Out of bounds pointer arithmetic NUMBER bytes NUMBER elements past end of array Non Fatal Run time Error Pointer arithmetic expression is invalid because the resulting value refers to a location past the end of an array The error message shows the number of bytes and number of array elements past the end Out of memory for user protection information Fatal Run time Error Could not allocate memory required to store user protection information Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 30 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 31 LabWindows CVI Programmer Reference Manual Overflow in constant CONSTANT Compile Warning Value of a constant or constant expression exceeds the limits of the type Ensure that the value does not exceed the maximum value for the expression type Overflow in constant expression Compile Warning Value of a constant or constant expression exceeds the limits of
170. ette or the CD ROM directory for separate distribution Run Time Library DLLs The installation program always places the Run time Engine DLLs in the Windows system directory under Windows 95 and the Windows system32 directory under Windows NT Low Level Support Driver The Run time Engine loads the low level support driver if it is present when you start your standalone executable Several functions in the Utility Library require the low level support driver Refer to the function reference for CVILowLevelSupportDriverLoaded in Chapter 8 Utility Library of the LabWindows CVI Standard Libraries Reference Manual for more information on these functions The installation program installs the low level support driver in the Windows system directory under Windows 95 and the Windows system32 drivers directory under Table 7 1 LabWindows CVI Run Time Engine Files Run Time Engine File Description cvirt dll Helper DLL cvirte dll Contains most LabWindows CVI libraries cviauto dll Contains ActiveX Automation Library cvi95vxd vxd Low level support driver for Windows 95 cvintdrv sys Low level support driver for Windows NT msgrtn txt Contains text messages n is Run time Engine version number cvirtn rsc Contains binary resources n is Run time Engine version number ni7seg ttf Font description file nisystem ttf Font description file 00ProRef book 06chap07 fm Page 10 Monday March 9 1998 3 23 PM Chapter 7 Creating a
171. eturn type If you did not intend for the function to return a value you must declare it as a void function Otherwise you must use a return statement to return a value Missing return value Compile Warning Non void function does not return a value Add a return statement with an expression of the function return type The compiler issues the diagnostic if the Require Return Value for Non void Functions compiler option is enabled Missing right bracket Fatal Run time Error Format string has mismatched brackets Missing struct tag Compile Error Tag name is missing from an incomplete struct or union declaration Missing terminating null in string argument Fatal Run time Error Library function expects a string argument but the argument you passed points to an array of characters that is not null terminated Missing union tag Compile Error Tag name is missing from an incomplete struct or union declaration Multiply defined symbol NAME in modules FILE1 and FILE2 Link Error The files being linked contain more than one definition for NAME Naked functions are not supported Compile Error LabWindows CVI does not work with the naked keyword NAME is a predefined macro and cannot be the subject of an undef Compile Error Make sure that the name you specify for the undef preprocessor directive is not that of a predefined macro Table A 1 Error Messages Continued Error
172. ference Manual and the LabWindows CVI function panel help list You can use the function GetDDEErrorString to get the error message associated with each DDE Library error code ActiveX Automation Library The ActiveX Automation Library functions return a negative value when they detect an error This library uses a common set of error codes Refer to the LabWindows CVI Standard Libraries Reference Manual or the function panel help for a listing of the error codes and information on the individual functions You can use CA_GetAutomationErrorString to get the error message associated with each ActiveX Automation Library error code X Property Library The X Property Library functions return a negative value when they detect an error This library uses a common set of error codes which the LabWindows CVI Standard Libraries Reference Manual and the LabWindows CVI function panel help list You can use the function GetXPropErrorString to get the error message associated with each X Property Library error code Formatting and I O Library This library contains the file I O string manipulation and data formatting functions All functions return negative error codes when they detect an error However you must keep in mind an important fact When you enable debugging the LabWindows CVI environment keeps track of the sizes of strings and arrays If it detects any attempt to access a string or array beyond its boundary the environment halts the program
173. fferences among compilers and platforms The following are examples of using the DLLEXPORT macro int DLLEXPORT DLLSTDCALL MyFunc int parm int DLLEXPORT myVar 0 If the type of your variable or function requires an asterisk in the syntax put the qualifier after the asterisk as in the following example char DLLEXPORT myVar NULL Note Borland C C version 4 5x requires that you place the qualifier before the asterisk In Borland C C 5 0 you can place the qualifier on either side of the asterisk When LabWindows CVI creates a DLL it exports all symbols for which export qualifiers appear in either the definition or the declaration If you use an export qualifier on the definition and an import qualifier on the declaration LabWindows CVI exports the symbol The external compilers differ widely in their behavior on this point Some require that the declaration and definition agree Note If you include in your DLL project an object or library file that defines exported symbols LabWindows CVI cannot correctly create import libraries for each of the external compilers This problem does not arise if you use only source code files in your DLL project Marking Imported Symbols in Include File Distributed with DLL If your DLL might be used in a C or C environment you must distribute an include file with your DLL The include file must declare all the symbols the DLL exports If any of these symbols are variables you mu
174. follows the include preprocessor directive Ensure that a filename of the correct form follows include or that any macro that follows include expands into the correct form for an include filename Missing Compile Error Termination single quote character is missing from a character or wide character literal Missing CHAR Compile Error Check for unterminated string or character literal Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 25 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 26 National Instruments Corporation Missing argument to variable argument function Fatal Run time Error Variable argument function requires at least one argument beyond the last formal parameter Missing array size Compile Error You attempted to define a block scope object or type that is an array which has an element type that is an incomplete array type such as an array with unspecified size The array element type must be a complete array type such as an array type with a known size Missing format string integer Non Fatal Run time Error Integer that corresponds to an asterisk in a format string is missing Incorrect ordering of the arguments can cause this This integer must precede the actual argument Missing identifier Compile Error Identifier that specifies the object nam
175. formation in them As a result you must be careful when you use jmp_buf and sigjmp_buf objects among multiple files In particular if you compile a file in LabWindows CVI with debugging enabled and the file uses setjmp or longjmp then your program must include the LabWindows CVI version of setjmp h to handle those functions correctly The same is true for sigjmp_buf sigsetjmp and siglongjmp 00ProRef book 06chap05 fm Page 11 Monday March 9 1998 3 23 PM National Instruments Corporation 6 1 LabWindows CVI Programmer Reference Manual 6 Building Multiplatform Applications This chapter contains guidelines and caveats for writing platform independent LabWindows CVI applications LabWindows CVI currently runs under Windows 3 1 and Windows 95 NT for the PC and Solaris 1 and Solaris 2 for the SPARCstation One major feature of LabWindows CVI is that it supports multiplatform programming Following a few simple guidelines assures the portability of a LabWindows CVI application Write code in strict ANSI C Observe and repair all LabWindows CVI compile link and run time diagnostics Avoid using system dependent calls when possible Avoid using non portable image formats and fonts in your user interface Multiplatform Programming Guidelines LabWindows CVI is portable because it uses ANSI C program files LabWindows CVI User Interface Resource files and National Instruments libraries You must segregate
176. g InvokeIndirectFunction __static_ClearAsyncWrite if IsError retval replace with macro to check if retval is error if gAsyncWriteAlias 0 Free16BitAlias gAsyncWriteAlias gAsyncWriteSize gAsyncWriteAlias 0 gAsyncWriteSize 0 return retval You can terminate LabWindows CVI programs in the middle of execution and then re run them When you terminate the program you should also terminate the asynchronous I O You can arrange to be notified of changes in the run state by including a function with the name RunStateChangeCallback in the obj or lib file associated with the DLL You can add this function to the glue code file Refer to the Notification of Changes in Run State section of Chapter 2 Using Loadable Compiled Modules of this manual for a complete description of the run state change notification In the example we have been discussing you should add the following code include libsupp h void CVICALLBACK __RunStateChangeCallback int newState if newState kRunState_Stop ClearAsyncWrite If the DLL Calls Directly Back into 32 Bit Code If the DLL calls directly back into 32 bit code you must modify the glue code source file You can call functions defined in 32 bit source code directly from a DLL Although this method is not as straightforward as Windows messaging it is not subject to the latencies of Window messaging For more information about Windows messaging refer to the Rec
177. g callback references from 3 10 to 3 12 linking to callback functions not exported from DLL 3 11 to 3 12 user libraries See also libraries installing 2 3 similarity with instrument driver 2 3 using loadable compiled modules 2 3 user protection dynamic memory 1 15 library functions 1 16 pointer casting 1 14 stack size 1 16 to 1 17 unions 1 16 user protection errors disabling 1 12 to 1 14 for individual pointer 1 12 to 1 13 library errors for functions 1 13 to 1 14 at run time 1 12 at run time 1 12 error category 1 8 general protection errors 1 11 library protection errors 1 11 to 1 12 memory corruption fatal 1 11 memory deallocation non fatal 1 11 pointer arithmetic non fatal 1 8 to 1 9 pointer assignment non fatal 1 9 pointer casting non fatal 1 10 pointer comparison non fatal 1 10 pointer dereference errors fatal 1 9 to 1 10 00ProRef book 11Index fm Page 13 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 14 National Instruments Corporation pointer subtraction non fatal 1 10 severity level 1 8 Utility Library 9 7 V va_arg ap type 1 2 VISA Library 9 5 Visual Basic See Microsoft Visual Basic Visual C C See Microsoft Visual C C VXI Library 9 4 W Watcom C C 32 bit compiled modules under Windows 3 1 4 1 to 4 2 creating object and library files 3 19 default directives 3 16 pull in references 3 17 stack based cal
178. ge 26 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 27 LabWindows CVI Programmer Reference Manual include files For more information refer to the Setting Up Include Paths for LabWindows CVI ANSI C and SDK Libraries section later in this chapter The number of SDK include files is very large Normally you have to include only windows h because it includes many but not all of the other include files The inclusion of windows h along with its subsidiary include files significantly increases compilation time and memory usage WIN32_LEAN_AND_MEAN is a macro from Microsoft that speeds compiling by eliminating the less commonly used portions of windows h and its subsidiary include files By default LabWindows CVI adds DWIN32_LEAN_AND_MEAN as a compile time definition when you create a new project You can alter this setting by using the Compiler Defines command in the Options menu of the Project window Using Windows SDK Functions for User Interface Capabilities The LabWindows CVI User Interface Library uses the Windows SDK It is not designed to be used in programs that attempt to build other user interface objects at the SDK level While no specific restrictions exist on using SDK functions in LabWindows CVI National Instruments recommends that you base your user interface either entirely on the LabWindows CVI User Interface Library or entirely on another user interface
179. get command in the Build menu Refer to Chapter 3 Project Window in the LabWindows CVI User Manual for detailed information on the Create Dynamic Link Library command You can debug the DLLs you create in LabWindows CVI Refer to the DLL Debugging Windows 95 NT Only section in Chapter 3 Project Window of the LabWindows CVI User Manual for more information Customizing an Import Library If you have to perform special processing in your DLL import library you can customize it Instead of generating a lib file you can generate a c file that contains source code If you do this however you can export only functions from the DLL not variables 00ProRef book 06chap03 fm Page 20 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 21 LabWindows CVI Programmer Reference Manual To customize an import library you must have an include file that contains the declarations of all the functions you want to export from the DLL Load the include file into a Source window and execute the Generate DLL Import Source command in the Options menu After you have generated the import source you can modify it including making calls to functions in other source files Create a new project that contains the import source file and any other files it refers to Select Static Library from the submenu attached to the Target command in the Build menu of the Project window Execute the Cre
180. get operating system Chapter 3 Windows 95 NT Compiler Linker Issues Chapter 4 Windows 3 1 Compiler Linker Issues and Chapter 5 UNIX Compiler Linker Issues of this manual discuss operating system requirements Using a Loadable Compiled Module as an External Module You can load a compiled module dynamically from your program A module you load dynamically is called an external module You can load execute and unload this external module programmatically using LoadExternalModule GetExternalModuleAddr and UnloadExternalModule Refer to Chapter 8 Utility Library of the LabWindows CVI Standard Libraries Reference Manual for more information on using these functions While you develop and debug the external module you can list it in the project as a source file After you finish debugging the module you can compile it into an object file or a Windows 95 NT DLL External modules must adhere to the requirements outlined for the target operating system Chapter 3 Windows 95 NT Compiler Linker Issues Chapter 4 Windows 3 1 Compiler Linker Issues and Chapter 5 UNIX Compiler Linker Issues of this manual discuss operating system requirements Notification of Changes in Run State You might have to notify certain compiled modules whenever your program starts suspends continues or stops For example if a compiled module has asynchronous callbacks you must prevent the callbacks from executing when program execution suspends at a breakpoin
181. hap07 fm Page 4 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 5 LabWindows CVI Programmer Reference Manual Minimum System Requirements for UNIX To run a standalone executable you create using LabWindows CVI for UNIX your system must have the following Sun SPARCstation Solaris 1 x SunOS 4 1 2 or higher or Solaris 2 4 or higher At least 24 MB of RAM At least 32 MB of disk swap space Free hard disk space equal to 4 MB plus space to accommodate your executable and any files the executable requires Translating the Message File The message file called msgrtn txt where n is the version number of the Run time Engine is a text file that contains the error messages that the Run time Engine displays It resides in the bin directory of the Run time Engine installation directory You can translate the message file into other languages To translate the message file perform the following steps 1 Copy the file to another name so you have it as a backup 2 Use a text editor to modify msgrtn txt Translate only the text that is inside quotation marks You must not add or delete any message numbers 3 Execute the countmsg exe or countmsg utility on the file to encode it for use with the Run time Engine as in the following example countmsg msgrt5 txt Configuring the Run Time Engine This section applies to
182. he Build menu of the Project window When you do so LabWindows CVI invokes the Sun Solaris linker ld to link your programs to the Run time Engine shared library You can use an external compiler and linker to create an executable that uses the Run time Engine shared library Use the Generate Makefile command in the Build menu of the Project window to generate a UNIX makefile that corresponds to the currently loaded project and libraries The makefile invokes an external compiler to compile your source files and then it invokes the Sun Solaris linker ld to link the compiled files with the Run time Engine shared library Compatible External Compilers You can use the following external ANSI C compilers to compile source files for linking with the LabWindows CVI Run time Engine shared library GNU C Compiler gcc Sun C Compiler cc and acc Note Under Solaris 2 4 when linking the LabWindows CVI Shared Library with external ANSI C compiler the compiler displays a warning that states the shared library has an invalid type You can ignore this warning Static and Shared Versions of the ANSI C and Other Sun Libraries When you build a project for execution in the LabWindows CVI development environment LabWindows CVI links your program to the static versions of the Sun Solaris libraries libc a and libm a On the other hand when you create a standalone executable in the LabWindows CVI development environment LabWindows C
183. he following two pragmas enable and disable library checking for all the function declarations that occur after the pragma within a header or source file The pragmas affect only the functions declared in the file in which the pragmas occur These pragmas do not affect nested include files pragma EnableLibraryRuntimeChecking pragma DisableLibraryRuntimeChecking The following pragmas enable and disable library checking for a particular function You must declare the function before the occurrence of the pragma pragma EnableFunctionRuntimeChecking function pragma DisableFunctionRuntimeChecking function 00ProRef book 06chap01 fm Page 13 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 14 National Instruments Corporation These two pragmas enable and disable run time checking for a particular library function throughout the module in which they appear You can use them to override the effects of the EnableLibraryRuntimeChecking and DisableLibraryRuntimeChecking pragmas for individual functions If both of these pragmas occur in a module for the same function LabWindows CVI uses only the last occurrence Note These pragmas affect all protection including run time checking of function arguments for all calls to a specific library function To disable breaking on errors for a particular call to a library function use the Utility Library function SetBreakOnLibraryErrors
184. he operand of sizeof Syntactically a type name is a declaration of a function or an object of that type that omits the identifier Extraneous return value Compile Error Return statement appears in a void function and therefore no return value is necessary eliminate the expression from the return statement Failed to load DLL FILE Link Error LabWindows CVI could not find the DLL Ensure that it is in one of the default directories searched by Microsoft Windows or that it includes a complete path name Failed to open external module Object Load Error LabWindows CVI could not open the external module for loading Ensure that the external module has read access and that you did not inadvertently rename or delete it Field name expected Compile Error The compiler expects an identifier to follow a or gt Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 15 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 16 National Instruments Corporation Field name missing Compile Error Identifier is missing from a member field declaration in a struct or union type declaration Make sure that an identifier follows the member type specifier Format string integer is too big Non Fatal Run time Error Integer used in the format string is too large Found TYPE expected a function
185. he text segments of LabWindows CVI programs actually reside in the data segment of the LabWindows CVI process you must lock both text and data segments using plock PROCLOCK in order to lock all text into memory Note Your LabWindows CVI process must have superuser privileges to use the plock function UNIX Asynchronous Signal Handling The following signals have special meaning in LabWindows CVI SIGPOLL SIGIO and SIGPIPE The LabWindows CVI TCP Library installs signal handlers for SIGPOLL SIGIO and SIGPIPE If you use the TCP Library and you want to install handlers for these signals you must call the LabWindows CVI handlers when your handlers are called If you attempt to set the signal handler to SIG_DFL for these signals while running in the LabWindows CVI environment LabWindows CVI restores its own handlers SIGINT and SIGQUIT Normally the operating system generates these two signals when you type certain keystrokes lt Ctrl C gt and lt Ctrl gt in the window from which you invoke LabWindows CVI If one of these signals occurs while your program is running and you have not installed a handler for it LabWindows CVI suspends your program the next time it calls a function that processes events such as ProcessSystemEvents If your program does not call any event processing functions it continues to run SIGTERM LabWindows CVI treats SIGTERM as a stronger version of SIGINT and SIGQUIT If this signal o
186. hen you create a standalone executable program or DLL Refer to Chapter 9 Checking for Errors in LabWindows CVI for details about performing error checking in your code 00ProRef book 06chap07 fm Page 19 Monday March 9 1998 3 23 PM National Instruments Corporation 8 1 LabWindows CVI Programmer Reference Manual 8 Distributing Libraries and Function Panels This chapter describes how to distribute libraries add libraries to a user s Library menu and specify library dependencies How to Distribute Libraries You can distribute libraries for other users to include in their Library menu You must create a function panel fp for each library program file If you do not want to develop function panels for the library functions create a fp file without any classes or functions In that case LabWindows CVI loads the library at startup but does not include the library name in the Library menu This is useful when the library supports other libraries and contains no user callable functions Adding Libraries to User s Library Menu Normally users must manually add libraries to the Library menu using the Library Options command in the Project window Options menu However you can insert your libraries into the user s Library menu by modifying the user s cvi ini file under Windows 3 1 cvi ini under UNIX or the Registry under Windows 95 NT Under Windows 3 1 and UNIX the modini program is in the LabWindows CVI bin subdire
187. hese directories have priority over the default paths for the compiler s C library and SDK library include files You must choose the compiler options carefully LabWindows CVI tries to work with the default options for each compiler as much as possible In some cases however you have to choose options that override the defaults In other cases you must accept the defaults Microsoft Visual C C LabWindows CVI is compatible with all the defaults You must not use the following options to override the default settings Borland C C LabWindows CVI is compatible with all the defaults You must not use the following options to override the default settings J Unsigned Characters Zp Struct Member Alignment Ge Stack Probes Gh Profiling Gs Stack Probes a Data Alignment K Unsigned Characters u Turn Off Generation of Underscores N Test Stack Overflow p Pascal Calling Convention pr Register Calling Convention fp Correct Pentium FDIV Flaw 00ProRef book 06chap03 fm Page 18 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 19 LabWindows CVI Programmer Reference Manual Watcom C C You must use the following options to override the default settings If your external object calls LoadExternalModule or LoadExternalModuleEx you must also add the following compiler option d__NO_MATH_OPS
188. his font also denotes text from which you supply the appropriate word or value monospace Text in this font denotes text or characters that you should literally enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs functions filenames and extensions and for statements and comments taken from programs monospace bold Bold text in this font denotes the messages and responses that the computer automatically prints to the screen monospace italic Italic text in this font denotes that you must enter the appropriate words or values in the place of these items paths Paths in this manual are denoted using backslashes to separate drive names directories folders and files Related Documentation You may find the following documentation helpful while programming in LabWindows CVI Microsoft Developer Network CD Microsoft Corporation Redmond WA Programmer s Guide to Microsoft Windows 95 Microsoft Press Redmond WA 1995 Harbison Samuel P and Guy L Steele Jr C A Reference Manual Englewood Cliffs NJ Prentice Hall Inc 1995 00ProRef book 05atm fm Page xv Monday March 9 1998 3 23 PM About This Manual LabWindows CVI Programmer Reference Manual xvi National Instruments Corporation Customer Communication National Instruments wants to receive your comments on our p
189. implementation limitations Ensure that the header name is properly terminated with a gt or a or shorten the string literal Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 16 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 17 LabWindows CVI Programmer Reference Manual Ill formed constant integer expression Compile Error Constant integer expression that appears in a preprocessor directive is syntactically invalid Check the expression for trailing tokens Ill formed hexadecimal escape sequence xCHAR Compile Error Ensure that a hexadecimal character 0 9 a f or A F follows the x escape sequence introduction Ill formed hexadecimal escape sequence Compile Error Ensure that a hexadecimal character 0 9 a f or A F follows the x escape sequence introduction Illegal argument s to library function Fatal Run time Error One or more of the arguments to the library function are invalid Refer to the library documentation for the function Illegal case label Compile Error Case label appears outside the context of a switch statement Remove the case label Illegal character CHAR Compile Error Character or character escape sequence outside the legal character set for an ANSI C source file appears in a context other than a character string or character liter
190. indows 16 bit DLLs Windows 32 bit DLLs customer communication xvi B 1 to B 2 cvidir configuration option Windows 95 NT 7 7 CVIRTEHasBeenDetached function 3 3 cvirtx configuration option Windows 3 1 7 6 D Data Acquisition Library 9 4 data types allowable data types for compiler table 1 6 converting 16 bit source code to 32 bit source code 1 6 to 1 7 DDE Library 9 6 debugging levels Extended 1 8 setting 1 8 Standard 1 8 __declspec dllexport qualifier 1 3 3 22 __declspec dllimport qualifier 1 3 distributing libraries 8 1 to 8 3 adding to user s Library menu 8 1 to 8 2 specifying library dependencies 8 2 to 8 3 00ProRef book 11Index fm Page 3 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 4 National Instruments Corporation distributing standalone executables See standalone executables creating and distributing DLLEXPORT macro 1 4 3 22 to 3 23 DLLIMPORT macro 1 4 DllMain function in DLLs 3 3 DLLs See Windows 16 bit DLLs Windows 32 bit DLLs DLLSTDCALL macro 3 22 3 24 dlopen function Sun Solaris 5 2 documentation conventions used in manual xiv xv organization of manual xiii xiv related documentation xv doubles returning 3 7 DSTRules option 7 7 duplicate typedefs 1 4 dynamic memory protection 1 15 dynamic memory protection errors memory corruption fatal 1 11 memory deallocation non fatal 1 11 E Easy I O for DAQ Library
191. indows CVI automatically generates when it loads the DLL However you cannot use this method in the following cases The DLL requires special interface functions compiled outside of the DLL You expect to pass arrays bigger than 64 K to functions in the DLL You pass a pointer to a function in the DLL and the DLL uses the pointer after the function returns For example you pass an array to a function that starts an asynchronous I O operation The function returns immediately but the DLL continues to operate on the array You pass a function pointer to the DLL and the DLL calls the function later For example the DLL makes a direct callback into 32 bit code You pass to the DLL a pointer that points to other pointers Two examples of pointers that point to other pointers are an array of pointers and a structure pointer with pointer members The DLL returns pointers as return values or through reference parameters The DLL exports functions by ordinal value only If your DLL falls into any of these categories refer to the DLLs That Cannot Use Glue Code Generated at Load Time section of this chapter for details on how to proceed Otherwise refer to the DLLs That Can Use Glue Code Generated at Load Time section also in this chapter 00ProRef book 06chap04 fm Page 7 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 8 N
192. indows CVI compiler compatible with the commonly used C extensions in external compilers under Windows 95 NT Keywords That Are Not ANSI C Standard LabWindows CVI for Windows 3 1 accepts the non ANSI C keywords pascal PASCAL and _pascal but ignores them Calling Conventions Windows 95 NT Only You can use the following calling convention qualifiers in function declarations cdecl _cdecl __cdecl recommended _stdcall __stdcall recommended In Microsoft Visual C C Borland C C and Symantec C C the calling convention normally defaults to __cdecl if you do not use a calling convention qualifier You can 00ProRef book 06chap01 fm Page 2 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 3 LabWindows CVI Programmer Reference Manual however set options to cause the calling convention to default to __stdcall The behavior is the same in LabWindows CVI You can set the default calling convention to either __cdecl or __stdcall using the Compiler Options command in the Options menu of the Project window When you create a new project the default calling convention is __cdecl In Watcom C C the default calling convention is not __cdecl or __stdcall You must use the 4s 80486 Stack Based Calling option when you compile a module in Watcom for use in LabWindows CVI Refer to the Compatibility with External Compilers section in Chapter 3 Windows 95 NT Compiler Linker
193. ing Loadable Compiled Modules of this manual Using 32 Bit Watcom Compiled Modules under Windows 3 1 You must adhere to the following rules for a 32 bit Watcom compiled module obj or lib file You can call LabWindows CVI library functions If you make a call to the ANSI C Standard Library you must include the LabWindows CVI header files instead of the Watcom header files You cannot call Watcom C library functions outside the scope of the ANSI C Standard Library You can call open close read write lseek or eof but you must include lowlvlio h from LabWindows CVI You cannot call functions in the Windows Software Development Kit SDK install interrupts perform DMA or access hardware directly These tasks must be done with a Dynamic Link Library DLL The exception to this is that you can use the inp and outp functions You cannot define a function as PASCAL pascal or _pascal if you intend to call it from source code in LabWindows CVI Also you cannot use any non ANSI C standard 00ProRef book 06chap04 fm Page 1 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 2 National Instruments Corporation keywords such as far near or huge in the declaration of functions to be called from LabWindows CVI source code If your Watcom compiled module performs floating point operations you must use Watcom Version
194. inition to a new style definition that matches the function prototype declaration Constant expression must be integer Compile Error Constant integer expression is expected in this context Ensure the expression conforms to the semantics of a constant expression that computes an integer value Conversion from TYPE to TYPE is compiler dependent Compile Warning Avoid converting between a function pointer and other types of pointers because you should not access functions as data and you cannot execute data as functions Could not allocate stack space Try decreasing the Maximum stack size option in the Run Options dialog Fatal Run time Error There is insufficient memory to allocate the Maximum Stack Size you have specified LabWindows CVI allocates the maximum size on the stack at the beginning of execution Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 10 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 11 LabWindows CVI Programmer Reference Manual Could not find the DLL header file HEADER FILE Glue Code Generation Error LabWindows CVI could not find the file that contains the prototypes for the functions in the DLL When generating glue code ensure that you specify the correct filename When loading a DLL ensure that a header file with the same base name as the DLL exists d m
195. ion National Instruments Corporation 6504 Bridge Point Parkway 512 794 5678 Austin Texas 78730 5039 00ProRef book 09CCApx fm Page 7 Monday March 9 1998 3 23 PM National Instruments Corporation G 1 LabWindows CVI Programmer Reference Manual Glossary Prefix Meaning Value m milli 10 3 micro 10 6 n nano 10 9 A active window The window user input affects at a given moment The title of an active window is highlighted API Application Programming Interface A set of functions exported by a library Array Display A mechanism for viewing and editing numeric arrays auto exclusion A mechanism that prevents pre existing lines from executing in the Interactive Execution window B binary control A function panel control that resembles a physical on off switch and can produce one of two values depending upon the position of the switch breakpoint An interruption in the execution of a program Breakpoint A function that interrupts the execution of a program Breakpoint command A specific command that interrupts the execution of a program 00ProRef book 10gloss fm Page 1 Monday March 9 1998 3 23 PM Glossary LabWindows CVI Programmer Reference Manual G 2 National Instruments Corporation C cdecl A function calling convention in which function calls pass arguments from right to left and the caller restores the stack position after the call check box A dialog box
196. ion be resumed through the Continue Step Over etc commands kRunState_Resume kRunState_EnableCallbacks user program execution resumes user program execution completes normally kRunState_DisableCallbacks kRunState_Stop 00ProRef book 06chap02 fm Page 5 Monday March 9 1998 3 23 PM Chapter 2 Using Loadable Compiled Modules LabWindows CVI Programmer Reference Manual 2 6 National Instruments Corporation Example 2 kRunState_Start kRunState_EnableCallbacks user program execution begins a breakpoint or run time error occurs or user presses the Terminate Execution key combination kRunState_DisableCallbacks kRunState_Suspend program execution suspends CVI environment resumes user selects the Terminate Execution command kRunState_DisableCallbacks even though callbacks already disabled kRunState_AbortingExecution long jump out of user program kRunState_DisableCallbacks even though callbacks already disabled kRunState_Stop Note A Resume notification does not always follow a Suspend notification A Stop notification can follow a Suspend notification without an intervening Resume notification Note Run state change callbacks do not work if you link your program in an external compiler Also external compilers report link errors if you have multiple run state change callbacks Using Run State Change Callbacks in a DLL You can include o
197. ions contains a pointer to dynamic memory that you deallocated with the free function Once memory is free all pointers into that block of memory are invalid Pointer arithmetic involving pointer to function Non Fatal Run time Error Pointer arithmetic expression is invalid because one of the subexpressions is a function pointer Pointer arithmetic involving uninitialized pointer Non Fatal Run time Error Pointer arithmetic expression is invalid because one of the subexpressions contains an uninitialized pointer It is probably an uninitialized local variable Pointer comparison involving address of nonarray object Non Fatal Run time Error One of the pointer expressions in the comparison is invalid because it does not point into an array Both expressions in pointer comparisons must point into the same object Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 32 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 33 LabWindows CVI Programmer Reference Manual Pointer is invalid Non Fatal Run time Error Pointer argument to the function contains an invalid address Pointer points to freed memory Non Fatal Run time Error Pointer argument to the function points to memory that you already freed Pointer subtraction involving address of nonarray object Non Fatal Run time Error One
198. ir Windows Only 7 7 useDefaultTimer Windows Only 7 7 DSTRules 7 7 UNIX Options 7 7 Necessary Files for Running Executable Programs 7 8 Necessary Files for Using DLLs Created in Windows 95 NT 7 9 Location of Files on the Target Machine for Running Executables and DLLs 7 9 LabWindows CVI Run Time Engine under Windows 95 NT 7 10 Run Time Library DLLs 7 10 Low Level Support Driver 7 10 00ProRef book 00ProRefTOC fm Page x Monday March 9 1998 3 23 PM Contents National Instruments Corporation xi LabWindows CVI Programmer Reference Manual Message Resource and Font Files 7 11 National Instruments Hardware I O Libraries 7 11 LabWindows CVI Run Time Engine under Windows 3 1 7 11 LabWindows CVI Run Time Engine under Sun Solaris 7 12 R
199. isted in the PATH environment variable Therefore Step 5 makes it easier for you to use VXIplug amp play instrument driver DLLs in LabWindows CVI for Windows 3 1 If the dll file is not associated with a fp file LabWindows CVI uses the following search precedence to find the DLL 1 If a pth file is in the project list LabWindows CVI uses the standard Windows DLL search algorithm The pth file must contain the name of the dll file such as mystuff dll It must contain an absolute path or a simple filename 2 If the dll file is in the project list then LabWindows CVI uses the absolute pathname to find the dll file 00ProRef book 06chap04 fm Page 23 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 24 National Instruments Corporation If you call LoadExternalModule on the dll file then If you specify it with an absolute pathname LabWindows CVI loads that file If you specify it with a relative pathname LabWindows CVI searches for the dll file in the following places and order indicated 1 In the project list 2 In the directory in which the project file is located 3 Among other modules already loaded 4 In the directories specified in the documentation for the Windows SDK LoadLibrary function In this case the include file for the DLL must be in the project or in one of the include paths you specify in the
200. istribute DLLs as separate files The operating system finds the DLL associated with the loaded import library using the standard Windows DLL search algorithm The search precedence is as follows 1 The directory from which the application loads 2 The current working directory 3 Under Windows 95 the Windows system directory Under Windows NT the Windows system32 and system directories 4 The Windows directory 5 The directories the PATH environment variable lists Using LoadExternalModule on DLL and Path Files under Windows 3 1 DLL files and DLL path files are never linked into the executable so you must distribute them as separate files Your executable can call LoadExternalModule directly on a DLL or DLL path file only if you include the DLL or DLL path file in the project When you select Create Standalone Executable File LabWindows CVI automatically creates the DLL glue code and links it into the executable Also you can pass the DLL glue object module filename to LoadExternalModule You can generate the DLL glue object module by opening the h file for the DLL in a Source window of LabWindows CVI and selecting Generate DLL Glue Object from the Options menu If you include the DLL the DLL path file or the DLL glue object module as a file in the project you must pass LoadExternalModule a simple filename and it uses the following search method to find the DLL 1 Look for a pth file in the directory of the execu
201. ive Expecting integer constant push or pop Compile Error pack pragma requires at least one parameter Extra default label Compile Error default label has already appeared for this switch statement Eliminate the extraneous default label Extraneous 0 width bit field TYPE NAME ignored Compile Warning Named bit field has no width and therefore has no storage allocated to it Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 14 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 15 LabWindows CVI Programmer Reference Manual Extraneous formal parameter specification Compile Error This error occurs when the compiler is processing what it assumes to be an old style function declaration and encounters what it assumes to be the function s parameter names If this is an old style function declaration make sure that the parameter names appear only in the function definition and not in any declaration of that function If this is a new style function declaration prototype then probably the identifier that the compiler assumes to be a parameter name is really a typedef name Make sure that you previously declared the identifier as a typedef Extraneous identifier NAME Compile Error Identifier appears in a context where the compiler expects a type name such as in a cast operation or as t
202. ject LabWindows CVI uses the standard Windows DLL search algorithm The pth file must contain the name of the dll file such as mystuff dll It must contain an absolute path or a simple filename 2 If a dll file with the same full path name as the fp file is in the project LabWindows CVI uses the absolute path of the dll file in the project to load the dll file 3 If a pth file with the same base name as the fp file is in the same directory as the fp file and a lib or obj file of the same base name does not exist in the same directory LabWindows CVI uses the standard Windows DLL search algorithm The pth file must contain the name of the dll file such as mystuff dll It must not contain any directory names or slashes 4 If a dll file with the same base name as the fp file is in the same directory as the fp file LabWindows CVI loads the dll file as long as no lib obj or pth file of the same base name appears in the same directory 5 If a pth or dll file does not appear in the same directory as the fp file LabWindows CVI uses the standard Windows search algorithm to look for a DLL with the same base name as the fp file Thus if a DLL with the same base name is in the windows or windows system directory or a directory listed in your PATH environment variable LabWindows CVI finds it DLLs for VXIplug amp play drivers are not in the same directory as the fp files but the directory that contains the DLL is l
203. l user interface GUI multiplatform application considerations 6 3 H hardware interrupts under Windows 95 NT 3 29 hot keys multiplatform application considerations 6 3 I image files accessing from standalone executables 7 12 multiplatform application considerations 6 3 using with standalone executables 7 9 import libraries Windows 95 NT automatic loading of SDK import libraries 3 27 to 3 28 compatibility with external compilers 3 5 customizing DLL import libraries 3 20 to 3 21 00ProRef book 11Index fm Page 5 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 6 National Instruments Corporation generating DLL import library 3 4 link errors when using DLL import libraries 3 2 import qualifiers _import 1 3 __import 1 3 marking imported symbols in include file 3 23 to 3 24 purpose and use 1 2 to 1 3 include files ANSI C library and LabWindows CVI libraries 3 10 generating glue code 4 9 Windows 32 bit DLLs exporting DLL functions and variables 3 22 marking imported symbols in include file 3 23 to 3 24 Windows SDK functions 3 26 to 3 27 include paths setting up for LabWindows CVI ANSI C and SDK libraries 3 28 to 3 29 Include Paths command Options menu 1 17 3 28 InitCVIRTE calling UNIX executables 5 4 to 5 5 Windows 95 NT executables 3 14 to 3 15 Insert Constructs command Edit menu 3 3 Instrument Directories command Options menu 8 2 instrum
204. l way of communicating with a DLL is to call functions in the DLL However cases exist where other communication methods are necessary The most typical case is that of an interrupt service routine in a DLL that must notify the application that the interrupt occurred In cases like this you must communicate with the DLL through a callback function LabWindows CVI recognizes messages posted by a DLL through the Windows SDK function PostMessage and can initiate a user callback function This method is useful for hardware interrupts but it is subject to the latency associated with Windows messaging LabWindows CVI uses RegisterWinMsgCallback UnRegisterWinMsgCallback and GetCVIWindowHandle to recognize Windows messages from a DLL You can call these functions from a module compiled in Watcom or from source code For complete information on these functions refer to the function descriptions in Chapter 4 User Interface Library Reference of the LabWindows CVI User Interface Reference Manual To use these functions call RegisterWinMsgCallback and GetCVIWindowHandle Pass their return values the message number and the window handle to the DLL When the DLL sends a message it calls PostMessage with these values When LabWindows CVI receives the message it calls the callback function Note LabWindows CVI can receive the message only when it is processing events LabWindows CVI processes events when it is waiting for user input If the program you
205. le A file that contains information about the function tree and function panels of an instrument module function panel A screen oriented user interface to the LabWindows CVI libraries in which you can interactively execute library functions and generate code for inclusion in a program Function Panel Editor window The window in which you build a function panel The LabWindows CVI Instrument Driver Developers Guide function panel window The window in which you can use function panels function tree The hierarchical structure in which the functions in a library or an instrument driver are grouped The function tree simplifies access to a library or instrument driver by presenting functions organized according to the operation they perform as opposed to a single linear listing of all available functions Function Tree Editor window The window in which you build the skeleton of a function panel file It is described in the LabWindows CVI Instrument Driver Developers Guide G Generated Code box A small box located at the bottom of the function panel screen that displays the function call code that corresponds to the current state of the function panel controls global control A function panel control that displays the contents of global variables in a library function Global controls allow you to monitor global variables in a function that the function does not specifically return as results by the function These are read only co
206. le external compilers can use Load object files library files and DLL import libraries created with any of the four compatible external compilers Call Windows Software Development Kit SDK functions This chapter discusses these capabilities Loading 32 Bit DLLs under Windows 95 NT Under Windows 95 NT LabWindows CVI can load 32 bit DLLs LabWindows CVI links to DLLs through the standard 32 bit DLL import libraries that you generate when you create 32 bit DLLs with any of the compilers Because LabWindows CVI links to DLLs in this way you cannot specify a DLL file directly in your project You must specify the DLL import library file instead 00ProRef book 06chap03 fm Page 1 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 2 National Instruments Corporation DLLs for Instrument Drivers and User Libraries Under Windows 95 NT LabWindows CVI does not directly associate DLLs with instrument drivers or user libraries However LabWindows CVI can associate instrument drivers and user libraries with DLL import libraries Each DLL must have a DLL import library lib file In general if the program for an instrument driver or user library is in the form of a DLL you must place the DLL import library in the same directory as the function panel fp file The DLL import library specifies the name of the DLL that LabWindows CVI searches for using th
207. lease resources release resources including unloading DLLs break It is always safe to call into the LabWindows CVI Run time Engine in a run state change callback If your DLL uses global variables that can become stale after each program execution in the LabWindows CVI development environment re initialize the variables in response to the kRunState_Start or kRunState_Stop message For example memory that you allocate using LabWindows CVI ANSI C functions such as malloc or calloc is no longer valid when you restart your program If your DLL has global variables that point to allocated memory set those pointers to NULL in response to the kRunState_Start or kRunState_Stop message Compiled Modules that Contain Asynchronous Callbacks A compiled module can call a source code function asynchronously This can happen through interrupts or signals In Windows 95 NT the compiled module can call the source code function from a thread other than the main thread The call takes place asynchronously with respect to the normal execution of the source code in your program The execution and debugging system in the LabWindows CVI development environment is not prepared to handle this asynchronous execution Consequently the compiled module must announce to LabWindows CVI that it is calling asynchronously into source code It does this by calling EnterAsyncCallback before calling the function and calling ExitAsyncCallback after calling
208. ling convention 3 15 Watcom WEMU387 386 coprocessor emulation software 7 2 Windows 3 1 compiler linker issues 16 bit Windows DLLs See Windows 16 bit DLLs 32 bit Borland or Symantec compiled modules 4 2 to 4 3 32 bit Watcom compiled modules 4 1 to 4 2 modules compiled by LabWindows CVI 4 1 cvirtx option for configuring Run time Engine 7 6 distributing standalone executables math coprocessor software emulation 7 2 minimum system requirements 7 2 structure packing pragmas 1 4 to 1 5 Windows 16 bit DLLs creating with Borland C 4 22 with Microsoft Visual C 1 5 4 21 to 4 22 DLLs unable to use glue code generated at load time 4 8 to 4 20 arrays bigger than 64 K 4 9 to 4 11 buffer retained after function returns asynchronous function 4 11 to 4 12 direct callbacks into 32 bit code 4 12 to 4 15 functions exported by ordinal value only 4 20 loading 4 8 to 4 9 pointer that points to other pointers 4 18 to 4 20 returning pointers 4 15 to 4 17 rules for include file 4 9 support module required outside of DLL 4 9 DLLs using glue code generated at load time 4 8 fixing linker error note 4 7 helpful LabWindows CVI options 4 4 not supported in Windows 95 NT 3 2 overview 4 3 to 4 4 requirements 4 7 rules and restrictions 4 5 to 4 7 search precedence 4 23 to 4 24 for standalone executables definition 7 9 loading with LoadExternalModule 7 17 to 7 18 rules for using 7 13 to 7 14 unusable in specific
209. m requirements for standalone executables 7 1 to 7 2 missing return value non fatal error 1 11 modini program caution 8 2 8 3 modreg program caution 8 2 8 3 multiplatform applications building externally compiled module issues 6 3 library portability issues 6 1 to 6 2 predefined macros 6 1 programming guidelines 6 1 to 6 3 user interface guidelines 6 3 multithreading creating multiple threads with Windows SDK functions 3 27 using LabWindows CVI libraries 3 8 N _NI_mswin_ macro 6 1 _NI_mswin16_ macro 6 1 _NI_mswin32_ macro multiplatform programming 6 1 required for external compilers 3 8 _NI_sparc_ macro 6 1 _NI_unix_ macro 6 1 O o files loading with LoadExternalModule 7 14 using with standalone executables 7 9 object files compatibility with external compilers Windows 95 NT 3 5 creating in external compilers for use in LabWindows CVI 3 18 to 3 19 in LabWindows CVI 3 26 loading with LoadExternalModule 7 14 using with standalone executables 7 9 Options menu Function Tree Editor Generate Windows Help command 3 25 Project window Compiler Defines command 1 2 3 27 Compiler Options command 1 2 Include Paths command 1 17 3 28 Instrument Directories command 8 2 Run Options command 1 8 1 12 1 16 00ProRef book 11Index fm Page 8 Monday March 9 1998 3 23 PM Index National Instruments Corporation I 9 LabWindows CVI Programmer Reference Manual Source Interactive Exec
210. n You can either not use this option by setting it to None or insert __loadds in front of every function you export from the DLL You can make the compiler export a function by inserting __export between the return type and the function name or by adding the function name to the exports section of the def file If you add the function name to the exports section of the def file remember to convert the name to all caps if you use the PASCAL calling convention or pre append an underscore if you use the CDECL calling convention Byte align structure members by choosing 1 Byte for the Options Project Compiler Code Generation Struct Member Byte Alignment Creating 16 bit DLLs with Borland C Consider the following issues or project options when you create a DLL with Borland C 4 x Every function you call from outside the DLL must be far exported and must load the data segment into the DS register The function must load the DS register if you want to use any non local variables in a function Use the large or huge memory model The savings you gain by using smaller memory models is not worth having to use the far keyword throughout your code This project option is in 16 bit Compiler Memory Model Mixed Model Override You can make the compiler load the data segment into the DS register by setting the project option 16 bit Compiler Memory Model Assume SS Equals DS to Never or by inserting _load
211. n LabWindows CVI has the following disadvantages You cannot debug compiled modules Because compiled modules do not contain any debugging information you cannot set breakpoints or view variable values Compiled modules do not include run time error checking or user protection Using a Loadable Compiled Module as an Instrument Driver Program File An instrument driver is a set of high level functions with graphical function panels to make programming easier It encapsulates many low level operations such as data formatting and GPIB RS 232 and VXI communication into intuitive high level functions An instrument driver usually controls a physical instrument but it also can be a software utility The Using Instrument Drivers and Instrument Menu sections of Chapter 3 Project Window of the LabWindows CVI User Manual describe how to use instrument drivers To develop and debug an instrument driver load its program file into LabWindows CVI as a source file After you finish debugging it you can compile the program file into an object file or a Windows 95 NT DLL The next time you load the instrument driver LabWindows CVI loads the compiled module which loads and runs faster that the source module Refer to the LabWindows CVI Instrument Driver Developers Guide for information on how to create an instrument driver 00ProRef book 06chap02 fm Page 2 Monday March 9 1998 3 23 PM Chapter 2 Using Loadable Compiled Modules N
212. n object or static library file from a DLL you might want to resolve references from that module using global symbols the DLL contains but does not export You can do this by calling LoadExternalModuleEx When you pass the DLL module handle to LoadExternalModuleEx the Utility Library searches the symbol table the DLL contains before searching the table that the executable contains Refer to Chapter 8 Utility Library of the LabWindows CVI Standard Libraries Reference Manual for detailed information on LoadExternalModuleEx If you create your DLL in LabWindows CVI LabWindows CVI includes the table of symbols in the DLL automatically If you create your DLL using an external compiler the external compiler does not make such a table available to the Utility Library Thus when you use an external compiler you must include in your DLL one or more object files that contain the necessary symbol tables You can do this using the technique that the previous section Resolving References to Symbols Not in Run Time Engine describes You must call InitCVIRTE and CloseCVIRTE in your DLLMain function Refer to the Calling InitCVIRTE and CloseCVIRTE section later in this chapter Run State Change Callbacks Are Not Available in External Compilers When you use a compiled module in LabWindows CVI you can arrange for LabWindows CVI to notify the module of a change in the execution status such as start stop suspend or resume You do this through a callback fu
213. n of Files on the Target Machine for Running Executables and DLLs section in this chapter for more information 2 Create a directory containing your executable program and associated files Structure the directory exactly as you want it to appear after installation To test your program run it from that directory 3 Use the shell script makedist in the misc bin directory to create a distribution package This script creates a compressed tar file that contains the directory you created in Step 2 and a copy of the LabWindows CVI Run time Engine 4 Make a copy of the installation script INSTALL sample in the misc bin directory and customize it using the information makedist provides This installation script unpacks a distribution package creating a directory like the one you created in Step 2 and then installs the LabWindows CVI Run time Engine The installation script can install from floppy disks or from the current directory 5 If you want to distribute your program on floppy disks use the shell script makefloppy in the misc bin directory to copy your installation script and distribution package to floppy disks If you want to distribute using some other method such as anonymous FTP you must provide users with the package file that makedist creates and the customized installation script that extracts the files from the package You can use this method under Solaris 2 if you do not want to use the pkgmk utility 00ProRef book 06c
214. n time errors because you set a pointer to dynamic memory in a source module and you then resize it in an object module The following steps describe how this error occurs 1 You declare a pointer in a source module you compile with debugging enabled You then assign to the pointer an address that malloc or calloc returns AnyType ptr ptr malloc N 2 You reallocate the pointer in an object module so that it points to the same location in memory as before This might occur if you call the realloc function or free the pointer and then reassign it to memory that you allocate with malloc ptr realloc ptr M M gt N or free ptr ptr malloc M 3 You use the same pointer in a source module you compile with debugging enabled At this point LabWindows CVI still expects the pointer to point to a block of memory of the original size N ptr M 1 This generates a fatal run time error even though it is a legal expression To prevent this error use the DISABLE_RUNTIME_CHECKING macro to disable checking for the pointer after you allocate memory for it in the source module ptr malloc N DISABLE_RUNTIME_CHECKING ptr Disabling Library Protection Errors for Functions You can disable or enable library protection errors by placing pragmas in the source code LabWindows CVI ignores these pragmas when you compile without debugging information that is if the debugging level is None For example t
215. nCmdShow C Library Issues This section discusses special considerations in LabWindows CVI in the areas of low level I O functions and the UNIX C library Using the Low Level I O Functions Many functions in the UNIX libraries and the C compiler libraries for the PC are not ANSI C Standard Library functions In general LabWindows CVI implements the ANSI C Standard Library Under UNIX you can call UNIX libraries for the non ANSI C functions in conjunction with LabWindows CVI The low level I O functions open close read write lseek and eof are not in the ANSI C Standard Library Under UNIX these functions are available in the UNIX C library Refer to Chapter 5 UNIX Compiler Linker Issues for more information Under Windows you can use these functions along with sopen and fdopen if you include lowlvlio h 00ProRef book 06chap01 fm Page 5 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 6 National Instruments Corporation C Data Types and 32 Bit Compiler Issues This section introduces the LabWindows CVI compiler data types and discusses converting 16 bit source code to 32 bit source code Data Types Table 1 2 shows the LabWindows CVI allowable data types The size of an enumeration type depends on the value of its enumeration constant In LabWindows CVI characters are signed unless you explicitly declare them unsigned The types float and double confo
216. nDetached function in the Utility Library It is always safe to call the CVIRTEHasBeenDetached function CVIRTEHasBeenDetached returns FALSE until the main Run time Engine DLL cvirte dll receives the PROCESS_DETACH message Consequently if CVIRTEHasBeenDetached returns FALSE your DLL can safely call functions in LabWindows CVI Run time Engine to release resources 00ProRef book 06chap03 fm Page 3 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 4 National Instruments Corporation Note cvirte dll contains the User Interface Utility Formatting and I O RS 232 ANSI C TCP and DDE Libraries Generating an Import Library If you do not have a DLL import library or if the one you have contains references the DLL does not export you can generate an import library in LabWindows CVI You must have an include file that contains the declarations of all the functions and global variables you want to access from the DLL The calling conventions of the function declarations in the include file must match the calling convention of the functions in the DLL For example if the DLL exports functions using the __stdcall calling convention the function declarations in the include file must contain the __stdcall keyword Load the include file into a Source window and select the Generate DLL Import Library command in the Options menu Default Unloading Reloading Policy S
217. namic Allocation in Function Parameters The LabWindows CVI run time error checking mechanism dynamically allocates data to keep track of pointers that you dynamically allocate in your program When you no longer use the pointers LabWindows CVI uses garbage collection to deallocate its corresponding dynamic memory A case exists where the garbage collection fails to retrieve all the memory it allocated This occurs when you pass the return value of one function to another function the return value is a pointer to dynamically allocated memory and you do not assign the pointer to a variable in the argument expression The following is an example MyFunc 1 2 malloc 7 This call passes the return value from malloc to MyFunc but does not assign it to a variable If you make this call repeatedly in your program with run time checking enabled you lose a small amount of memory each time Change the code as follows to avoid this problem void p MyFunc 1 2 p malloc 7 The following code also works and uses better programming style void p p malloc 7 MyFunc 1 2 p 00ProRef book 06chap01 fm Page 15 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 16 National Instruments Corporation Library Functions The LabWindows CVI library functions that take pointer arguments or that return pointers incorporate run time checking for those arguments and retu
218. nction that is always named __RunStateChangeCallback The Notification of Changes in Run State section in Chapter 2 Using Loadable Compiled Modules of this manual describes this in detail The run state change callback capability in LabWindows CVI is necessary because the LabWindows CVI development environment executes your program as part of the LabWindows CVI process When your program terminates the operating system does not release resources as it does when a process terminates LabWindows CVI attempts to release 00ProRef book 06chap03 fm Page 13 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 14 National Instruments Corporation resources your program allocated but your compiled module might have to do more Also if the program suspends for debugging purposes your compiled module might have to disable interrupts When you run an executable created in an external compiler it always executes as a separate process even when you debug it Thus the run state change callback facility is not necessary and does not work External compilers report link errors when you define __RunStateChangeCallback in more than one object file If you include a run state change callback in a compiled module that you intend to use both in LabWindows CVI and an external compiler it is a good idea to put the callback function in a separate source file and create a lib file in
219. nd Distributing Standalone Executables and DLLs National Instruments Corporation 7 11 LabWindows CVI Programmer Reference Manual Windows NT Under Windows NT the installation program also adds a registry entry under the following key HKEY_LOCAL_MACHINE SYSTEM ControlSet001 Services cvintdrv Table 7 2 shows the values the installation program sets for the Windows NT registry entry for the low level support driver Message Resource and Font Files The installation program installs ni7seg ttf and nisystem ttf in the cvirte fonts subdirectory under the directory in which it installs the Run time Engine DLLs It installs the msgrtn txt and cvirtn rsc in the cvirte bin subdirectory under the directory in which it installs the Run time Engine DLLs It sets the cvidir option in the following registry key to the pathname of the cvirte directory HKEY_LOCAL_MACHINE Software National Instruments CVI Run Time Engine cvirte You can subsequently change the location of the bin and fonts subdirectories but you must also change the cvidir registry option to the pathname of the directory that contains the two subdirectories National Instruments Hardware I O Libraries The LabWindows CVI Run time Engine does not include the DLLs or drivers for National Instruments hardware Users can install the DLLs and drivers for their hardware from the distribution disks that National Instruments supplies LabWindows CVI Run Time Engine under Windows 3 1
220. nd topics used in this manual including the page where each one can be found Conventions Used in This Manual The following conventions are used in this manual lt gt Angle brackets enclose the name of a key on the keyboard for example lt Shift gt A hyphen between two or more key names enclosed in angle brackets denotes that you should simultaneously press the named keys for example lt Ctrl Alt Delete gt The symbol leads you through nested menu items and dialog box options to a final action The sequence File Page Setup Options Substitute Fonts directs you to pull down the File menu select the Page Setup item select Options and finally select the Substitute Fonts options from the last dialog box 00ProRef book 05atm fm Page xiv Monday March 9 1998 3 23 PM About This Manual National Instruments Corporation xv LabWindows CVI Programmer Reference Manual This icon to the left of bold italicized text denotes a note which alerts you to important information This icon to the left of bold italicized text denotes a caution which advises you of precautions to take to avoid injury data loss or a system crash bold Bold text denotes the names of menus menu items parameters or dialog box buttons bold italic Bold italic text denotes an activity objective note caution or warning italic Italic text denotes variables emphasis a cross reference or an introduction to a key concept T
221. ne or more run state change callbacks in a DLL To do so you must build the DLL in the LabWindows CVI development environment and each run state change callback must be in a separate object or static library file in the DLL project If you include a run state change callback in a DLL or in an object or static library file that another user might include in a DLL take special care in two areas Use caution when you call into other DLLs in response to a kRunState_Stop message When you use your DLL in a standalone executable the DLL receives the kRunState_Stop message when the executable terminates The order in which 00ProRef book 06chap02 fm Page 6 Monday March 9 1998 3 23 PM Chapter 2 Using Loadable Compiled Modules National Instruments Corporation 2 7 LabWindows CVI Programmer Reference Manual Windows 95 NT unloads DLLs at process termination is not well defined Therefore the DLL you call into might no longer be loaded This can cause a general protection fault Nevertheless when you use your DLL in a program in the LabWindows CVI development environment it is often necessary to call into DLLs to release resources after each run To solve this dilemma use conditional code to release resources only if you are running in the LabWindows CVI development environment An example follows include lt utility h gt switch runState case kRunState_Stop if InStandaloneExecutable call into other DLLs to re
222. ng window management systems that LabWindows CVI uses You must not assign the forward lt Delete gt key as a hot key in your user interface because that key does not exist on all platforms 00ProRef book 06chap06 fm Page 3 Monday March 9 1998 3 23 PM National Instruments Corporation 7 1 LabWindows CVI Programmer Reference Manual 7 Creating and Distributing Standalone Executables and DLLs This chapter describes how the LabWindows CVI Run time Engine DLLs externally compiled modules and other files interact with your executable file This chapter also describes how to perform error checking in a standalone executable program You can create executable programs from any project that runs in the LabWindows CVI environment Introduction to the Run Time Engine With your purchase of LabWindows CVI you received the Run time Engine as part of your distribution The LabWindows CVI Run time Engine is necessary to run executables or use DLLs you create with LabWindows CVI and it must be present on any target computer on which you want to run your executable program You can distribute the Run time Engine according to your license agreement Distributing Standalone Executables under Windows Under Windows you can bundle the LabWindows CVI Run time Engine with your distribution kit using the Create Distribution Kit command in the Build menu of the Project window or you can distribute it separately by making copies of the Run time
223. nly refer to the Rules for Using DLL Files under Windows 3 1 section earlier in this chapter For lib files by default Create Standalone Executable File or Create Dynamic Link Library only links in the library modules that you reference statically in the project Therefore you must force into the executable the modules that contain the functions you call using GetExternalModuleAddr To force these modules into the executable include the library file in the project and take one of the following actions If you want to force the entire library file into the executable use the Add Files to Executable button in the Create Standalone Executable File dialog box or the Add Files to DLL button in the Create Dynamic Link Library dialog box 00ProRef book 06chap07 fm Page 15 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 16 National Instruments Corporation If you want to force only specific modules from the library into the executable reference them statically in your program For example you could have an array of void pointers and initialize them to the names of the necessary symbols If you link in an external compiler under Windows 95 NT the LabWindows CVI Utility library does not know the location of symbols in the externally linked executable or DLL Consequently without further action on your part you cannot
224. ns You cannot call any Sun C Library function that uses data types incompatible with the LabWindows CVI compiler or libraries In particular you must not call functions that use the long double data type In LabWindows CVI the long double data type has 8 bytes but the Sun libraries expect a 16 byte object Under Solaris 2 you must not call any function that uses the long long data type LabWindows CVI does not recognize this non ANSI type 00ProRef book 06chap05 fm Page 1 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues LabWindows CVI Programmer Reference Manual 5 2 National Instruments Corporation Using Shared Libraries in LabWindows CVI In the LabWindows CVI development environment you can link your programs to static libraries but not to shared libraries If you have to use a shared library you must use the Sun Solaris linker ld to build your application Refer to the Creating Executables that Use the LabWindows CVI Libraries section later in this chapter for more information on using external compilers and the Sun linker If you have both shared and static versions of a library you can develop and debug your application in the LabWindows CVI development environment using the static version of the library You can then create your final executable with the Sun linker using the shared version of the library Using dlopen The Sun Solaris dlopen function allows you to load shared libraries from your
225. nst const int Do not use the const and volatile qualifiers more than once each in the same type Illegal use of type name NAME Compile Error You used a typedef name in the context of a primary expression If you intended to use a type cast parenthesize the typedef name Otherwise you must use a macro name enumeration constant variable name or function name in this context Illegal value matched to asterisk Non Fatal Run time Error Integer argument that matches to an asterisk in the format string has an invalid value given the context in which it appears Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 20 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 21 LabWindows CVI Programmer Reference Manual Illegal variable declaration only static and extern variable classes are valid in the interactive window Compile Error Change the variable declaration to be either static or extern Import Variables cannot be used in global variable initialization Compile Error You used a global variable marked as __import or declspec dllimport in an initializer of another variable Include files nested too deeply Compile Error Number of nested include files exceeds compiler limits Reduce the number of nested include preprocessor directives Inconsistent linkage for NAME previously
226. nteger In most cases this does not cause a problem and the conversion is transparent because functions that use 2 byte integers in LabWindows for DOS use 4 byte integers in LabWindows CVI However this conversion does cause a problem when a program performs one of the following actions Passes an array of 16 bit integers to a GPIB VXI or Data Acquisition DAQ function If you use a 32 bit int array to receive a set of 16 bit integers from a device LabWindows CVI packs two 16 bit values into each element of the 32 bit array Any attempt to access the array on an element by element basis does not work Declare the array as short instead and make sure any type specifiers that refer to it have the b2 modifier when you pass them as an argument to a Formatting and I O Library function Uses an int variable in a way that requires it to be a 2 byte integer For example if you pass an int argument by address to a function in the Formatting and I O Library such as a Scan source or a Scan Fmt target and it matches a d b2 or i b2 specifier it does not work correctly Remove the b2 modifier or declare the variable as short Conversely if you pass a short argument by address and it matches a d or i specifier without the b2 modifier it does not work correctly Add the b2 modifier Note The default for d is 2 bytes on a 16 bit compiler and 4 bytes on a 32 bit compiler In the same way the default for int is 2 bytes on a 1
227. nters point to memory that is not in the LabWindows CVI flat address space you cannot map them back into the normal 32 bit pointers that LabWindows CVI uses You can access them in Watcom object code by first converting them to 32 bit far pointers using the function MK_FP32 To access them in LabWindows CVI source code you must copy the data into a buffer you allocate in LabWindows CVI Notice that you cannot pass 16 or 32 bit far pointers to LabWindows CVI library functions and that LabWindows CVI does not provide access to the Watcom string and memory buffer manipulation functions that take far pointers as arguments You must write the loops to copy the data 00ProRef book 06chap04 fm Page 15 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 16 National Instruments Corporation Case 1 Assume the DLL has the following function char f char ptr sprintf ptr hello return ptr Then assume that a program in LabWindows CVI uses the function f as follows char buffer 240 char bufptr bufptr f buffer printf s bufptr You would have to modify the glue code as shown here char f char ptr char retval unsigned short cw387 cw387 Get387CW retval char InvokeIndirectFunction __static_f ptr Set387CW cw387 retval MapAliasToFlat retval Add this line to glue code return retval Case 2
228. ntrols that cannot be altered by the user and do not contribute a parameter to the generated code glue code Special code that provides the interface between 32 bit LabWindows CVI applications and 16 bit DLLs H hex Hexadecimal 00ProRef book 10gloss fm Page 3 Monday March 9 1998 3 23 PM Glossary LabWindows CVI Programmer Reference Manual G 4 National Instruments Corporation highlight The way in which input focus is displayed on a LabWindows CVI screen to move the input focus onto an item I immediate action command A menu bar item that has no menu items associated with it and causes a command to execute immediately when you select it An immediate action command is suffixed with an exclamation point input control A function panel control that accepts a value you type in from the keyboard An input control can have a default value associated with it This value appears in the control when the panel is first displayed input focus Displayed on the screen as a highlight on an item signifying that the item is active User input affects the item in the dialog box that has the input focus instrument driver A set of high level functions for controlling an instrument It encapsulates many low level operations such as data formatting and GPIB RS 232 and VXI communication into intuitive high level functions An instrument driver can pertain to one particular instrument or to a group of related instruments
229. odifier not valid in Fmt FmtOut FmtFile Non Fatal Run time Error d modifier cannot be used in Fmt FmtOut or FmtFile Declaration of NAME does not match previous declaration at POSITION Compile Error You declared a variable or function twice and its type in the first declaration does not match its type in the second declaration Declared parameter NAME is missing Compile Error Declaration for a parameter in an old style parameter list is missing or the declaration does not match to any parameter name in the list Ensure that the names in the old style function definition have corresponding parameter declarations A better course is to convert the old style function definition to the new style function definition requiring prototypes defined expects an identifier argument Compile Error Preprocessor defined operator requires a single identifier argument ensure that you use an identifier and not an expression Dereference of a NUMBER byte object where only NUMBER bytes exist Fatal Run time Error Pointer expression you dereferenced points to an object that is smaller than the type of the dereference For example if an int pointer points to an object of type char you cannot dereference the pointer because it points to only 1 byte whereas an int requires 4 bytes Dereference of data pointer used as a function Fatal Run time Error You converted a data pointer to a function pointer
230. oft Visual C C 3 16 Symantec C C 3 16 Watcom C C 3 16 Watcom pull in references 3 17 Windows messages passed from DLLs 4 21 GetCVIWindowHandle function 4 21 RegisterWinMsgCallback function 4 21 UnRegisterWinMsgCallback function 4 21 00ProRef book 11Index fm Page 16 Monday March 9 1998 3 23 PM Index National Instruments Corporation I 17 LabWindows CVI Programmer Reference Manual Windows SDK functions 3 26 to 3 28 automatic loading of SDK import libraries 3 27 to 3 28 calling in LabWindows CVI 3 26 to 3 28 creating multiple threads 3 27 include files 3 26 to 3 27 setting up include paths for SDK libraries 3 28 to 3 29 user interface capabilities 3 27 X X Property Library status reporting by 9 6 00ProRef book 11Index fm Page 17 Monday March 9 1998 3 23 PM
231. ognizing Windows Messages Passed from a DLL section of this chapter Note If you need direct callbacks to occur at interrupt time because the latency of Windows messaging is interfering with your application contact National Instruments for assistance 00ProRef book 06chap04 fm Page 12 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 13 LabWindows CVI Programmer Reference Manual You cannot pass pointers to 32 bit functions directly into 16 bit DLLs The Windows SDK interface for this is very complex Generate DLL Glue Source does not generate this code for you You must write your own glue code for passing function pointers to and from a DLL and add it to the file that Generate DLL Glue Source generates Suppose a DLL contains the following functions long FAR savedCallbackPtr long long FAR InstallCallback long FAR callbackPtr long savedCallbackPtr callbackPtr long InvokeCallback long data return savedCallbackPtr data After you use the Generate DLL Glue Source command to generate the glue code for these functions you must modify the code as follows Note Because direct callbacks must be declared far and LabWindows CVI cannot compile far functions you must declare a far function in the glue code and pass it to the DLL This far function calls the actual user function undef MakeProcInstance Use version that does not c
232. ok 07AppA fm Page 41 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 42 National Instruments Corporation Undefined symbol NAME Link Error You used a variable or function in the project but did not define it anywhere Unexpected elif endif expected Compile Error Compiler encountered an else preprocessor directive immediately prior to this elif at the same level of conditional inclusion Ensure that the conditional preprocessor include directives at this level are in the proper order Unexpected elif if not seen Compile Error Compiler encountered an elif preprocessor directive but it has not yet seen a beginning if ifdef or ifndef at this level Unexpected else endif expected Compile Error Compiler encountered an else preprocessor directive immediately following a prior else at the same level of conditional inclusion Ensure that the conditional preprocessor include directives at this level are in the proper order Unexpected else if not seen Compile Error Compiler encountered an else preprocessor directive but it has not yet seen a beginning if ifdef or ifndef at this level Unexpected endif no matching if ifdef or ifndef Compile Error Compiler encountered an endif preprocessor directive but has not yet seen a beginning if ifdef or ifndef at this level Unexpected EOF Load Er
233. ome fundamental differences exist in the way Windows 95 NT and Windows 3 1 handle a DLL that multiple processes use Windows 95 NT creates a separate data space for each process that uses the DLL Windows 3 1 creates only one data space for all processes that use the DLL Windows 95 NT notifies a DLL each time a process loads or unloads it Windows 3 1 does not notify a DLL each time a process loads or unloads it Windows 3 1 notifies the DLL only when the first process loads it and the last process unloads it LabWindows CVI for Windows 95 NT unloads DLLs by default after each execution of a user program in the development environment This behavior more accurately simulates what happens when you execute a standalone executable and it is more suitable for Windows 95 NT DLLs that rely on load unload notification on each execution of a program You can change the default behavior by turning off the Unload DLLs After Each Run option in the Run Options dialog box of the Project window National Instruments recommends however that you leave the default behavior in effect Compatibility with External Compilers LabWindows CVI for Windows 95 NT can be compatible at the object code level with any of the four compatible external compilers Microsoft Visual C C Borland C C Watcom C C and Symantec C C Because these compilers are not compatible with each other at the object code level LabWindows CVI can be compatible with only one external
234. on Regardless of the method you use to link the import library you must distribute the subsidiary DLL separately The import library always contains the name of the subsidiary DLL When your executable or DLL is loaded the operating system finds the subsidiary DLL using the standard DLL search algorithm which the Windows SDK documentation for the LoadLibrary function describes The search precedence is as follows 1 The directory from which the user loads the application 2 The current working directory 3 Under Windows 95 the Windows system directory Under Windows NT the Windows system32 and system directories 4 The Windows directory 5 The directories listed in the PATH environment variable The Create Distribution Kit command automatically includes in your distribution kit the DLLs that the import libraries in your project refer to You must add to the distribution kit any DLLs that you load through LoadExternalModule or that you load by calling the Windows SDK LoadLibrary function Do not include DLLs for National Instruments hardware in your distribution kit The user must install these DLLs from the distribution disks that National Instruments supplies Rules for Using DLL Files under Windows 3 1 LabWindows CVI never links DLL files and DLL path files into the executable so you must distribute them as separate files The Create Distribution Kit command automatically includes DLLs that your project refers to in your
235. on portable even between these two systems To use an externally compiled module across platforms you must recompile the source code for the module with a compiler for the target system Multiplatform User Interface Guidelines Function panel fp files are portable across platforms User Interface Resource uir files are portable across platforms Image file formats other than PCX pcx are not portable Color hue and intensity differences between platforms are unavoidable The only fonts sure to be available on all platforms are the National Instruments fonts National Instruments fonts of the same name resemble each other stylistically from one platform to another although some relative size differences might exist The National Instruments Meta Fonts are of uniform size height relative to the rest of the user interface and are the most portable family of fonts available However the width of the National Instruments Meta Fonts might differ slightly from one platform to another Allow for extra space in the width of all control labels to assure consistent appearance You might find the User Interface library functions GetCtrlBoundingRect GetTextDisplaySize and GetScreenSize useful in calculating and compensating for font size discrepancies between platforms The order in which LabWindows CVI processes user interface events might differ between Windows and UNIX platforms This happens because of differences between the underlyi
236. onday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 19 LabWindows CVI Programmer Reference Manual Illegal return type found TYPE expected TYPE Compile Error Return statement expression type is not the same as the return type of the function in which it appears Ensure that the type of the return expression is consistent assignment compatible with the function return type Illegal separator character or illegal position of separator character Non Fatal Run time Error Either the separation characters lt and gt were not present in the format string or they were in the wrong place Illegal source filename specified for line s char sequence expected Compile Error Only token that can follow the line number specification in a line preprocessor directive is an optional string literal specifying a source filename A sequence of tokens also can follow the line token if after the compiler performs macro expansion on the source line the source line conforms to one of the two allowable forms of line preprocessor directives line line number digit sequence line line number digit sequence filename Illegal statement termination Compile Error During compilation of a sequence of statements the compiler encountered a token that it expected either to begin a new statement begin an else clause of an if statement be a statement label be a case
237. ontinued Error Message Type Error Comment 00ProRef book 07AppA fm Page 29 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 30 National Instruments Corporation Operands of have incompatible calling conventions Compile Error Function pointer is assigned an expression that does not match its calling convention Operands of one from set of binary operators have illegal types TYPE and TYPE Compile Error Types of the two operands to the binary operator are illegal according to the ANSI C standard Operands of one from set of binary operators have incompatible types Compile Error Types of the two operands to the binary operator are not compatible according to the ANSI C standard Operand of unary OPERATOR has illegal type TYPE Compile Error Type of the operand to the unary operator is not valid Out of bounds pointer argument before start of array Fatal Run time Error Pointer expression you passed to the library function is invalid because it refers to a location that is before the start of an array The expression is probably the result of previous illegal pointer arithmetic Out of bounds pointer argument past end of array Fatal Run time Error Pointer expression you passed to the library function is invalid because it refers to a location past the end of an array The expression is probably the r
238. onvert pointer undef FreeProcInstance Use version that does not convert pointer typedef struct Holds resources required to register the callback int UserDefinedProcHandle CALLBACKPTR proc16 FARPROC proc16Instance CallbackDataType static CallbackDataType CallbackData static long UsersCallback long Define a 32 bit far callback whose address is passed to the DLL It calls your function using function pointer stored in UsersCallback 00ProRef book 06chap04 fm Page 13 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 14 National Instruments Corporation static long FAR CallbackHelper long data return UsersCallback data Modified glue code for the function that installs the callback long InstallCallback long callback long long retval unsigned short cw387 UsersCallback callback Store CVI 32 bit pointer in static variable Create a 16 bit thunk for the 32 bit far function CallbackHelper if CallbackData UserDefinedProcHandle GetProcUserDefinedHandle 0 return FALSE Too many callbacks installed or handles not freed if DefineUserProc16 CallbackData UserDefinedProcHandle PROCPTR CallbackHelper UDP16_DWORD UDP16_CDECL UDP16_ENDLIST goto failed if CallbackData proc16 GetProc16 PRO
239. ou must use LabWindows CVI to generate an object file that contains a table of those symbols Create an include file that contains complete declarations of all the symbols your run time modules reference from the executable The include file can contain nested include statements and can contain executable symbols that your run time modules do not refer to If your run time 00ProRef book 06chap03 fm Page 12 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 13 LabWindows CVI Programmer Reference Manual module references any of the commonly used Windows SDK functions you can use the cvi sdk include basicsdk h file Execute the External Compiler Support command in the Build menu of the Project window A dialog box appears Enable the Using Load External Module option Enable the Other Symbols checkbox if it is not already enabled Enter the pathname of the include file in the Header File control Enter the pathname of the object file to generate in the Object File control Click on the Create button to the right of the Object File control Include the object file in the external compiler project you use to create your executable Also you must call InitCVIRTE at the beginning of your main or WinMain function Refer to the Calling InitCVIRTE and CloseCVIRTE section later in this chapter Resolving Run Time Module References to Symbols Not Exported from a DLL When you load a
240. pes that use it Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 13 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 14 National Instruments Corporation Error at or near character NUMBER in the format string STRING Non Fatal Run time Error Error exists in the format string at index NUMBER NUMBER is 1 based Error in Elf Library encountered while reading external module NAME Object Load Error Object module is corrupted or is of a type that LabWindows CVI cannot load Error compiling FILE for DLL exports DLL Import Library Creation Error When creating a DLL using the Include File method for specifying exported symbols an error occurred while compiling the include file Error Incompatible type for function or variable NAME in header FILE used to specify exports DLL Link Error When creating a DLL using the Include File method for specifying exported symbols the type of the symbol in the include file did not match the type in the source file Expecting an enumerator identifier Compile Error Compiler expects an enumeration constant identifier after the opening in an enum type declaration Expecting an identifier Compile Error Compiler expects an identifier in the current syntactic context Check the syntax of the declaration statement or preprocessor direct
241. piler for Linking in an External Compiler Use the SDK and ANSI C include files from the external compiler This happens automatically Specify the following directories as include paths in the external compiler for the LabWindows CVI library include files cvi include 00ProRef book 06chap03 fm Page 28 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 29 LabWindows CVI Programmer Reference Manual Compiling in an External Compiler for Linking in LabWindows CVI Use the LabWindows CVI SDK and ANSI C include files Specify the following directories as include paths in the external compiler cvi include cvi include ansi cvi sdk include Handling Hardware Interrupts under Windows 95 NT Under Windows 3 1 you can handle hardware interrupts in a DLL Under Windows 95 you must handle hardware interrupts in a VxD Under Windows NT you must handle hardware interrupts in a kernel mode driver You cannot create VxDs and kernel mode drivers in LabWindows CVI Instead you must create them in Microsoft Visual C C and you also must have the Microsoft Device Driver Developer Kit DDK Under Windows 3 1 it is extremely difficult to call source code into LabWindows CVI at interrupt time Making such a call is easier under Windows 95 NT Under Windows 95 NT you can arrange for the VxD or kernel mode driver to call a function in your LabWindows CVI source code after the interru
242. piler to create a obj or lib file to be loaded with the DLL If you also have interface functions that must exist outside the DLL you must combine them with the glue code to form the obj or lib file Loading a DLL That Cannot Use Glue Code Generated at Load Time If you have a 32 bit Watcom compiled obj or lib file that contains glue code for a DLL LabWindows CVI must load the obj or lib file first For instance if you want to use x dll and x obj in your program add x obj to the project Do not add x dll to the project The obj or lib file causes LabWindows CVI to load the dll The obj or lib file must contain the glue code for the DLL It is the presence of the glue code that indicates to LabWindows CVI that a dll is associated with the obj or lib file When LabWindows CVI loads the obj or lib file and finds that it contains glue code it first looks for the dll in the same directory as the obj or lib file If it cannot find the dll LabWindows CVI looks for it using the standard Windows DLL search algorithm 00ProRef book 06chap04 fm Page 8 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 9 LabWindows CVI Programmer Reference Manual Also you can create a pth file in the same directory as the obj or lib file with the same base name The pth file must contain a simple filename or a full pathname of the DLL If it is a simple filename LabWindow
243. poration Using Externally Compiled Modules In general you can load objects compiled with the Sun compilers and the GNU gcc compiler into LabWindows CVI with a few restrictions Restrictions on Externally Compiled Modules You can use externally compiled modules with the following restrictions The objects must not use any data types that are incompatible with the LabWindows CVI compiler or libraries Incompatible data types include the following long double with any Sun compilers A Sun compiler implements long double as a 16 byte object but LabWindows CVI implements it as an 8 byte object long long with the Solaris 2 Sun compiler LabWindows CVI does not support this non ANSI type Any enumeration type Many compilers implement enumeration types with different sizes and values You cannot load a Solaris 2 object file when you run LabWindows CVI under Solaris 1 However you can load Solaris 1 objects when you run under Solaris 2 Compiling Modules With External Compilers You can compile external modules using LabWindows CVI header files instead of the headers the compiler supplies To compile this way you must define the preprocessor macro _NI_sparc_ to the value 1 for Solaris 1 or to the value 2 for Solaris 2 When using the Sun ANSI C compiler use the I flag to add the LabWindows CVI include directory to the search list as shown in the following command lines Solaris 1 acc Xc I home cvi in
244. precision or double precision ordinal number A numeric value that corresponds to a function within a DLL The linker that creates the DLL arbitrarily defines it or it may be specified in the def file when the DLL is created P PASCAL A Windows 3 1 function calling convention in which function arguments are passed left to right and the function restores the stack pointer before it returns Project window A window that contains a list of files your application uses prompt command A command that requires additional information before it can be executed a prompt command appears on a pull down menu suffixed with an ellipsis 00ProRef book 10gloss fm Page 5 Monday March 9 1998 3 23 PM Glossary LabWindows CVI Programmer Reference Manual G 6 National Instruments Corporation R return value control A function panel control that displays a value returned from a function as a return value rather than as a formal parameter ring control A function panel control that represents a range of values much like the slide control but displays only a single item in a list rather than displaying the whole list at once as the slide control does Each item has a different value associated with it This value is placed in the function call rvalue Any C expression that is not an lvalue Examples of rvalues are array names functions function calls such as f assignment expressions such as x e and cast expressions s
245. program dynamically Although this function can work in some cases when running in LabWindows CVI it can make LabWindows CVI unstable If you use dlopen to load shared libraries in a program you run in LabWindows CVI the shared libraries might link to the system libraries the LabWindows CVI environment uses As a result functions in the shared library might modify the LabWindows CVI environment and cause unpredictable behavior The LabWindows CVI Run Time Engine as a Shared Library The LabWindows CVI development environment contains many built in libraries such as the User Interface Library and Utility Library LabWindows CVI also provides these libraries in the form of a standalone shared library called the LabWindows CVI Run time Engine All executables that call LabWindows CVI library functions use the Run time Engine shared library This is true whether you build the executable in the LabWindows CVI development environment or with an external compiler and the Sun Solaris linker 00ProRef book 06chap05 fm Page 2 Monday March 9 1998 3 23 PM Chapter 5 UNIX Compiler Linker Issues National Instruments Corporation 5 3 LabWindows CVI Programmer Reference Manual Creating Executables that Use the LabWindows CVI Libraries You can build executables that use the LabWindows CVI libraries in two ways You can build an executable in the LabWindows CVI development environment by selecting the Create Standalone Executable command in t
246. pt service routine exits You do this by creating a separate thread for your interrupt callback function The callback function executes a loop that blocks its thread until the interrupt service routine signals it Each time the interrupt service routine executes it unblocks the callback thread The callback thread then performs its processing and blocks again LabWindows CVI includes source code template files for a VxD and a kernel mode driver It also includes a sample main program to show you how to read and write registers on a board There is one set of files for Windows 95 and another for Windows NT The files are in cvi vxd win95 and cvi vxd winnt The file template doc in each directory contains some basic information 00ProRef book 06chap03 fm Page 29 Monday March 9 1998 3 23 PM National Instruments Corporation 4 1 LabWindows CVI Programmer Reference Manual 4 Windows 3 1 Compiler Linker Issues This chapter describes the different kinds of compiled modules available under LabWindows CVI for Windows 3 1 and includes programming guidelines for modules you generate with external compilers Using Modules Compiled by LabWindows CVI You can generate a compiled obj or o module from a source file within LabWindows CVI using the Create Object File command in the Options menu of a Source window You can then use the compiled module in any of the methods described in the About Loadable Compiled Modules section in Chapter 2 Us
247. r Reference Manual 2 Using Loadable Compiled Modules This chapter describes the advantages and disadvantages of using compiled code modules in your application It also describes the kinds of compiled modules available in LabWindows CVI and includes programming guidelines for modules you generate with external compilers Refer to Chapter 3 Windows 95 NT Compiler Linker Issues Chapter 4 Windows 3 1 Compiler Linker Issues or Chapter 5 UNIX Compiler Linker Issues in this manual for more information on platform specific programming guidelines for modules that external compilers generate About Loadable Compiled Modules Several methods exist for using compiled modules in LabWindows CVI You can load compiled modules directly into the LabWindows CVI environment as instrument driver programs or as user libraries so they are accessible to any project You can list compiled modules in your project so they are accessible only within that project You can use compiled modules dynamically in your program with LoadExternalModule RunExternalModule and UnloadExternalModule Any compiled module you use in LabWindows CVI must be in one of the following forms A obj file on the PC or a o file under UNIX that contains one object module A lib file on the PC or a a file under UNIX that contains one or more object modules A dll file that contains a Windows DLL Windows only You can create any of these compiled modules in
248. r filename of the form FILE or lt FILE gt is expected It is also possible that the header filename beginning quote character is different than the expected closing quote character such as lt FILE Illegal initialization for NAME Compile Error Ensure that the initialization is not for a function declaration rather than a pointer to a function Illegal initialization for parameter Compile Error Parameter declarations cannot have default value initializations in ANSI C Eliminate the initialization Illegal initialization for parameter NAME Compile Error Parameter declarations cannot have default value initializations in ANSI C Eliminate the initialization Illegal initialization of extern NAME Compile Error You attempted to initialize an extern declaration that appears in a local scope Eliminate the initialization Illegal return type TYPE Compile Error Function is declared with an illegal return type or a return statement expression type is not the same as the return type of the function in which it appears If the diagnostic is for a function declaration ensure that the return type is not an array type or a function type If the diagnostic is for a return statement the containing function is probably declared void and can contain no expression in its return statement Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 18 M
249. r of the Run time Engine The installation program installs the shared library in the lib subdirectory under the Run time Engine installation directory It also creates two symbolic links where cvirte stands for the Run time Engine installation directory as shown in Table 7 3 The installation program installs message and resource files in the bin directory under the Run time Engine installation directory It installs font description files in the fonts directory under the Run time Engine installation directory You can subsequently change the location of the bin and fonts subdirectories but you must also change the cvidir configuration option to the pathname of the directory that contains the two subdirectories The LabWindows CVI Run time Engine does not include the shared libraries or drivers for National Instruments hardware Users can install the shared libraries and drivers for their hardware from the distribution disks that National Instruments supplies Rules for Accessing UIR Image and Panel State Files on All Platforms The recommended method for accessing UIR image and panel state files in your executable program is to place the files in the same directory as the executable and pass simple filenames with no drive letters or directory names to LoadPanel DisplayImageFile SavePanelState and RecallPanelState If you do not want to store these files in the same directory as your executable you must pass pathnames to LoadPanel Displ
250. r written consent of National Instruments Corporation Trademarks CVI National Instruments the National Instruments logo natinst com and The Software is the Instrument are trademarks of National Instruments Corporation Product and company names listed are trademarks or trade names of their respective companies WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS National Instruments products are not designed with components and testing intended to ensure a level of reliability suitable for use in treatment and diagnosis of humans Applications of National Instruments products involving medical or clinical treatment can create a potential for accidental injury caused by product failure or by errors on the part of the user or application designer Any use or application of National Instruments products for or involving medical or clinical treatment must be performed by properly trained and qualified medical personnel and all traditional medical safeguards equipment and procedures that are appropriate in the particular situation to prevent serious injury or death should always continue to be used when National Instruments products are being used National Instruments products are NOT intended to be a substitute for any form of established process procedure or equipment used to monitor or safeguard human health and safety in medical or clinical treatment 00ProRef book 02Warr fm Page 3 Monday March 9 1998
251. ram to modify cvi ini or the Registry If LabWindows CVI is running while you use these programs you will lose your changes Specifying Library Dependencies When one library you distribute is dependent upon another library you distribute you can specify this dependency in the function panel file for the dependent library When LabWindows CVI loads the dependent library it attempts to load the libraries upon which it depends Use the FP Auto Load List command in the Edit menu of the Function Tree Editor window of the dependent library to list the fp files of the libraries upon which it depends Refer to the Function Tree Editor chapter of the LabWindows CVI Instrument Driver Developers Guide for details on this command LabWindows CVI can find the required libraries most easily when they are all in the same directory as the dependent library When you cannot put them in the same directory you must add the directories in which the required libraries reside to the user s Instrument Directories list The user can manually enter this information using the Instrument Directories command in the Project window Options menu Also you can add to the Instrument Directories list by editing cvi ini under Windows 3 1 cvi ini under UNIX or the Registry under Windows 95 NT 00ProRef book 06chap08 fm Page 2 Monday March 9 1998 3 23 PM Chapter 8 Distributing Libraries and Function Panels National Instruments Corporation 8 3 LabWindows C
252. rameters Too many initializers Compile Error Size of the initializer exceeds the size of the object Ensure that the initializer matches the number size of the object type Too many macro parameters Compile Error Number of parameter declarations exceeds compiler limitations Declare the macro with fewer parameters Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 39 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 40 National Instruments Corporation Too many parameters Non Fatal Run time Error Number of parameters you passed to a function exceed the number of parameters the format string expects Type error in argument d to s calling convention mismatch Compile Error Function or function pointer you passed to a function does not have the correct calling convention Type error in argument NUMBER to NAME TYPE is illegal Compile Error Argument you passed is an illegal array type or an incomplete type of which the size is unknown Ensure that the argument is of a complete type Type error in argument NUMBER to NAME found TYPE expected TYPE Compile Error You passed an argument that is not type compatible with the prototype declaration for the parameter in that position Ensure that the actual argument is type compatible with the parameter declaration Type er
253. rary directive and the linker does not explicitly include a C library in the link the linker reports unresolved function references in the object modules Object and static library files that LabWindows CVI creates do not contain a default library directive This has different implications for each compiler Microsoft Visual C C If you include in your project at least one object file that contains a default library directive the Visual C linker uses that library to resolve references in all object and library files even the files you create in LabWindows CVI Object files you create in Visual C usually contain default library directives If you do not include in your project any object files or libraries you create in Visual C you can add the following Visual C libraries to the project to avoid link errors libc lib oldnames lib In the Visual C development environment add these library names using the Input category in the Link tab of the Project Settings dialog box Borland C C No problems exist with the absence of default library directives when you use the Borland compiler Watcom C C Like Visual C at least one object file must contain a default library directive to cause the C library to be linked in In addition Watcom also requires a default library directive for floating point support If you do not include in your project any object files with the required directives add the following libraries in the order
254. ray Indexing and Pointer Protection Errors 1 8 Pointer Arithmetic Non Fatal 1 8 Pointer Assignment Non Fatal 1 9 Pointer Dereference Errors Fatal 1 9 Pointer Comparison Non Fatal 1 10 Pointer Subtraction Non Fatal 1 10 Pointer Casting Non Fatal 1 10 Dynamic Memory Protection Errors 1 11 Memory Deallocation Non Fatal 1 11 Memory Corruption Fatal 1 11 00ProRef book 00ProRefTOC fm Page v Monday March 9 1998 3 23 PM Contents LabWindows CVI Programmer Reference Manual vi National Instruments Corporation General Protection Errors 1 11 Library Protection Errors 1 11 Disabling User Protection 1 12 Disabling Protection Errors at
255. references you must add import libraries to your project Refer to the cvi sdk sdkfuncs txt file for associations of SDK import libraries to SDK functions The import libraries are in the cvi sdk lib directory Setting Up Include Paths for LabWindows CVI ANSI C and SDK Libraries The rules for using SDK include files are not the same as the rules for using ANSI C standard library include files which in turn are different than the rules for using the LabWindows CVI library include files Refer to the Include Files for the ANSI C Library and the LabWindows CVI Libraries and Windows SDK Include Files sections earlier in this chapter You must set up your include paths differently depending on the environment in which you compile and link A discussion of each case follows Compiling in LabWindows CVI for Linking in LabWindows CVI Use the LabWindows CVI SDK and ANSI C include files You do not have to set up any special include paths LabWindows CVI finds the correct include files automatically Compiling in LabWindows CVI for Linking in an External Compiler Use the LabWindows CVI SDK include files and the ANSI C include files from the external compiler Using the Include Paths command in the Options menu of the Project window add the following as explicit include paths at the beginning of the project specific list cvi include cvi sdk include directory containing the external compiler s ANSI C include paths Compiling in an External Com
256. register to the operating system The executable has an associated icon on which you can double click to start the application When the executable starts it loads the Run time Engine Under UNIX the executable returns the value that main returned or the value you passed to exit Run time Engine The Run time Engine contains all the built in library memory and program execution code present in the LabWindows CVI environment without all the program development tools such as the source editor compiler debugger and user interface editor The Run time Engine is smaller than the LabWindows CVI environment and thus loads faster and requires less memory You use only one copy of the Run time Engine on each target machine even when you have multiple executables Under UIR image amp state files DLLs amp PTHs external lib s or a s external obj s or o s other files Executable LW CVI Run Time Engine startup code compiled source code instrument driver code obj s or o s lib s or a s application name amp icon resource program execution support memory management built in CVI Libraries 00ProRef book 06chap07 fm Page 8 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 9 LabWindows CVI Programmer Reference Manual Windows 95 NT the Run time Engine consists of multiple files including thre
257. ring Source Code for Use in a DLL 3 21 Calling Convention for Exported Functions 3 21 Exporting DLL Functions and Variables 3 22 Include File Method 3 22 Export Qualifier Method 3 22 Marking Imported Symbols in Include File Distributed with DLL 3 23 Recommendations 3 24 Automatic Inclusion of Type Library Resource for Visual Basic 3 24 Creating Static Libraries in LabWindows CVI 3 25 Creating Object Files in LabWindows CVI 3 26 Calling Windows SDK Functions in LabWindows CVI 3 26 Windows SDK Include Files 3 26 Using Windows SDK Functions for User Interface Capabilities 3 27 Using Windows SDK Functions to Create Multiple Threads 3 27 Automatic Loading of SDK Import Libraries
258. rm to 4 byte and 8 byte IEEE standard formats Converting 16 Bit Source Code to 32 Bit Source Code If you convert a LabWindows for DOS application to a LabWindows CVI application use this section as a guide after you complete the steps in Chapter 12 Converting LabWindows for DOS Applications of the Getting Started with LabWindows CVI manual In general if you make few assumptions about the sizes of data types little difference exists between a 16 bit compiler and a 32 bit compiler except for the larger capacity of integers and the larger address space for arrays and pointers Table 1 2 LabWindows CVI Allowable Data Types Type Size Minimum Maximum char 8 128 127 unsigned char 8 0 255 short 16 32 768 32 767 unsigned short 16 0 65 535 int long int 32 2 31 2 31 1 unsigned int 32 0 2 32 1 unsigned long 32 0 2 32 1 float 32 3 40282E 38 3 40282E 38 double long double 64 1 79769E 308 1 79769E 308 pointers void 32 N A N A enum 8 16 or 32 2 31 2 31 1 00ProRef book 06chap01 fm Page 6 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 7 LabWindows CVI Programmer Reference Manual For example the code int x declares a 2 byte integer in a 16 bit compiler such as LabWindows for DOS In contrast a 32 bit compiler such as LabWindows CVI handles this code as a declaration of a 4 byte i
259. rmation on how to use the LabWindows CVI User Interface Library in a multithreaded program refer to Chapter 3 Programming with the User Interface Library in the LabWindows CVI User Interface Reference Manual 00ProRef book 06chap03 fm Page 8 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 9 LabWindows CVI Programmer Reference Manual Using LabWindows CVI Libraries in External Compilers Under Windows 95 NT you can use the LabWindows CVI libraries in any of the four compatible external compilers You can create executables and DLLs that call the LabWindows CVI libraries LabWindows CVI ships with the run time DLLs that contain all the libraries Executable files you create in LabWindows CVI also use these DLLs The cvi extlib directory contains DLL import libraries and a startup library all compatible with your external compiler Never use the lib files in the cvi bin directory in an external compiler You must always include the following two libraries in your external compiler project cvisupp lib startup library cvirt lib import library to DLL containing User Interface Library Formatting and I O Library RS 232 Library DDE Library TCP Library Utility Library You can add the following static library file from cvi extlib to your external compiler project analysis lib Analysis or Advanced Analysis
260. rn values However you must be careful when passing arguments to library functions that have void parameters such as GetCtrlAttribute and GetCtrlVal in the User Interface Library and memcpy and memset in the ANSI C library If you use a void cast when you pass an argument to a function that expects a variably typed argument you disable run time checking for that argument Some examples follow int value GetCtrlVal panel ctrl amp value CORRECT GetCtrlVal panel ctrl void amp value INCORRECT char names N namesCopy N memcpy namesCopy names sizeof names CORRECT memcpy void namesCopy void names sizeof names INCORRECT Unions LabWindows CVI performs only minimal checks for union type variables If a union contains pointers arrays or structs LabWindows CVI does not maintain user protection information for those objects Stack Size Your program uses the stack for passing function parameters and storing automatic local variables You can set the maximum stack size by selecting the Options Run Options in the Project window Table 1 3 shows the stack size ranges LabWindows CVI supports Table 1 3 Stack Size Ranges for LabWindows CVI Platform Minimum Default Maximum Windows 3 1 4 KB 40 KB 40 KB Windows 95 NT 100 KB 250 KB 1 MB Solaris 1 for Sun 100 KB 250 KB 5 MB Solaris 2 for Sun 100 KB 250 KB 5 MB 00ProRef book 06chap01 fm Page 16 Monday
261. roducts and manuals We are interested in the applications you develop with our products and we want to help you if you have problems with them To make it easy for you to contact us this manual contains comment and technical support forms for you to complete These forms are in Appendix B Customer Communication at the end of this manual 00ProRef book 05atm fm Page xvi Monday March 9 1998 3 23 PM National Instruments Corporation 1 1 LabWindows CVI Programmer Reference Manual 1 LabWindows CVI Compiler This chapter describes LabWindows CVI compiler specifics C language extensions 32 bit compiler issues debugging levels and user protection Overview The LabWindows CVI compiler is a 32 bit ANSI C compiler The kernel of the LabWindows CVI compiler is the lcc ANSI C compiler Copyright 1990 1991 1992 1993 David R Hanson It is not an optimizing compiler but instead focuses on debugging user protection and platform independence Because the compiler is an integral part of the LabWindows CVI environment and features a limited set of straightforward options it is also easy to use LabWindows CVI Compiler Specifics This section describes specific LabWindows CVI compiler limits options defines and diversions from the ANSI C standard Compiler Limits Table 1 1 shows the compiler limits for LabWindows CVI Table 1 1 LabWindows CVI Compiler Limits Coding Attribute Limit Maximum nesting of include 32
262. rom UIR Files When you link your program in LabWindows CVI LabWindows CVI keeps a table of the non static functions that are in your project When your program calls LoadPanel or LoadMenuBar the LabWindows CVI User Interface Library uses this table to find the callback functions associated with the objects you load from the user interface resource uir file This is true whether you run your program in the LabWindows CVI development environment or as a standalone executable 00ProRef book 06chap03 fm Page 10 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 11 LabWindows CVI Programmer Reference Manual When you link your program in an external compiler the external compiler does not make such a table available to the User Interface Library To resolve callback references you must use LabWindows CVI to generate an object file that contains the necessary table 1 Create a LabWindows CVI project that contains the uir files your program uses if you do not already have one 2 Select the External Compiler Support command in the Build menu of the Project window A dialog box appears 3 In the UIR Callbacks Object File control enter the pathname of the object file you want to generate When you click on the Create button LabWindows CVI generates the object file with a table that contains the names of all the callback functions referenced in all the uir files in
263. rom a DLL 3 11 Resolving References from Modules Loaded at Run Time 3 12 Resolving References to the LabWindows CVI Run Time Engine 3 12 Resolving References to Symbols Not in Run Time Engine 3 12 Resolving Run Time Module References to Symbols Not Exported from a DLL 3 13 Run State Change Callbacks Are Not Available in External Compilers 3 13 Calling InitCVIRTE and CloseCVIRTE 3 14 Watcom Stack Based Calling Convention 3 15 Using Object and Library Files in External Compilers 3 15 Default Library Directives 3 15 Microsoft Visual C C 3 16 Borland C C 3 16 Watcom C C 3 16 Symantec C C 3 16 Borland Static versus Dynamic C Libraries 3 17 Borland Incr
264. ror pointer expected Compile Error Expression you dereferenced with the gt or operator does not have pointer type TYPE is an illegal bit field type Compile Error Only int and unsigned types are valid for bit field declarations ensure that you use one of these types TYPE used as an lvalue Compile Warning Type that cannot be modified is used as the target of an assignment This was probably caused by an lvalue that is a dereference of an object declared as void Unclosed comment Compile Error Comment is missing the closing delimiter Undeclared identifier NAME Compile Error You did not previously declare NAME You must declare all names before use Ensure that you did not conditionally exclude NAME from compilation Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 40 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 41 LabWindows CVI Programmer Reference Manual Undefined label NAME Compile Error You used the label NAME as the target of a goto statement in the function but it never appears as a statement label Ensure the label appears in the same function as the goto statements of which it is a target Non local goto statements are illegal Undefined size for TYPE NAME Compile Error You have defined an object with an incomplete type Because the
265. ror LabWindows CVI encountered an unexpected End Of File EOF condition when loading an external object module Ensure that the object file has not been truncated Unexpected EOF TOKEN expected Compile Error The compiler encountered an End Of File EOF condition while parsing a syntactic construct Ensure that syntactic structure is complete such as matching parenthesis and matching braces Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 42 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 43 LabWindows CVI Programmer Reference Manual Unexpected end of format string Non Fatal Run time Error Format string you passed to the function is not complete It is missing a source or destination format specifier or contains an incomplete format specifier Unexpected token Compile Error Compiler encountered an unexpected token while processing a define preprocessor directive Check for missing in your macro parameter lists Unexpected trailing tokens on directive line ignored Compile Warning Preprocessor line contains harmless trailing tokens that the compiler ignored Uninitialized pointer Non Fatal Run time Error You never assigned a value to the pointer argument you passed to a function Uninitialized pointer argument to library function Fatal Run time Error Pointer expres
266. ror message associated with each VISA Library error code IVI Library The IVI Library functions return a negative value when they detect an error This library uses a common set of error codes Refer to the LabWindows CVI Instrument Driver Developers Guide or the function panel help for a listing of the error codes and information on the individual functions IVI Library functions sometimes also provide a secondary error code or an elaboration string to give you additional information about an error condition You can use Ivi_GetErrorInfo to obtain the primary error code secondary error code and the elaboration string You can use Ivi_GetErrorMessage to obtain the error message associated with each IVI Library error code 00ProRef book 06chap09 fm Page 5 Monday March 9 1998 3 23 PM Chapter 9 Checking for Errors in LabWindows CVI LabWindows CVI Programmer Reference Manual 9 6 National Instruments Corporation TCP Library The TCP Library functions return a negative value when they detect an error This library uses a common set of error codes which the LabWindows CVI Standard Libraries Reference Manual and the LabWindows CVI function panel help list You can use GetTCPErrorString to get the error message associated with each TCP Library error code DDE Library The DDE Library functions return a negative value when they detect an error This library uses a common set of error codes which the LabWindows CVI Standard Libraries Re
267. s LabWindows CVI error checking is sensitive to the requirements of each library function The following errors involve library protection Null pointer argument to library function Uninitialized pointer argument to library function Passing a pointer to freed memory to a library function Array argument too small Passing by reference a scalar argument to a library function that expects an array 00ProRef book 06chap01 fm Page 11 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 12 National Instruments Corporation Missing terminating null in string argument Passing a string to a library function that expects a character reference parameter LabWindows CVI library functions return error codes in a variety of cases If you enable the Break on Library Errors option in the Run Options command in the Options menu of the Project window LabWindows CVI suspends execution after a library function returns one of these errors A message appears that displays the name of the function and either the return value or a string that explains why the function failed Disabling User Protection Occasionally you might want to disable user protection to avoid run time errors that do not cause problems in your program Disabling Protection Errors at Run Time You can use the SetBreakOnProtectionErrors function in the Utility Library to programmatic
268. s 5 3 to 5 4 Windows 3 1 system requirements 7 1 to 7 2 Windows 95 NT 3 20 necessary files 7 9 system requirements 7 1 to 7 2 standard input output windows LabWindows CVI 3 10 state change notification for compiled modules See run state change notification for compiled modules state files See panel state files static libraries creating 3 25 status codes checking function call status codes 9 1 definition note 9 2 returned by LabWindows CVI functions 9 2 to 9 3 status reporting by libraries and instrument drivers 9 3 to 9 7 ActiveX Automation Library 9 6 Advanced Analysis Library 9 3 Analysis Library 9 3 ANSI C Library 9 7 Data Acquisition Library 9 4 00ProRef book 11Index fm Page 11 Monday March 9 1998 3 23 PM Index LabWindows CVI Programmer Reference Manual I 12 National Instruments Corporation DDE Library 9 6 Easy I O for DAQ Library 9 4 Formatting and I O Library 9 6 to 9 7 GPIB GPIB 488 2 Library 9 4 to 9 5 IVI Library 9 5 LabWindows CVI instrument drivers 9 7 RS 232 Library 9 5 TCP Library 9 6 User Interface Library 9 3 Utility Library 9 7 VISA Library 9 5 VXI Library 9 4 X Property Library 9 6 _stdcall calling convention qualifier 1 2 __stdcall calling convention qualifier creating static libraries note 3 25 creating static objects note 3 26 declaring functions for export 3 21 to 3 22 purpose and use 1 3 structure packing pragmas Windows 1 4 to 1 5 3 6 Sun
269. s error Aborted load of library FILE Link Error Library load operation aborted A more specific diagnostic of the library load error precedes this message Aborted load of member NAME from library FILE Link Error Library member load operation aborted A more specific diagnostic of the library member load error precedes this message Aborted load of object module FILE Link Error Object file load aborted A more specific diagnostic of the object file load error precedes this message Absolute segments not supported segment name NAME PC Windows Load Error OMF object file contains a segment to load at an absolute address Anonymous enum declared inside parameter list has scope only for this declaration Compile Warning Enumeration declared in the parameter list has scope only within the parameter list As a result its type is incompatible with all other types You must declare the enumeration type before declaring function types that use it Anonymous struct declared inside parameter list has scope only for this declaration Compile Warning Structure declared in the parameter list has scope only within the parameter list As a result its type is incompatible with all other types You must declare the structure type before declaring function types that use it Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 2 Monday March 9 1998
270. s CVI uses the standard Windows DLL search algorithm Rules for the DLL Include File Used to Generate Glue Source You can generate the DLL glue source file by opening the h file for the DLL in a Source window and selecting Generate DLL Glue Source from the Options menu This command prompts you for the name of a h file It puts the glue code in a c file with the same path and base name as the h file You must modify this c file as this section describes and compile it using the Watcom compiler Refer to the Using 32 Bit Watcom Compiled Modules under Windows 3 1 section of this chapter for information on how to use the Watcom compiler with LabWindows CVI If any of the functions in the DLL are declared as PASCAL pascal or _pascal you must declare them as PASCAL in the h file you use to generate the glue code LabWindows CVI ignores the PASCAL keyword except for the purposes of generating the glue code The stub function in the glue code is not declared as PASCAL If you include this h file in the glue code the Watcom compiler flags as an error the inconsistency between the declaration of the function in the h file and the definition of the stub function If you include it in other modules you compile under Watcom calls to the function erroneously compile as if the function were PASCAL You have two options Have two separate h files one that includes the PASCAL keyword and one that does not Use the one that does include the PASCAL
271. s during compilation of a type specification The specified TOKEN is not valid in the context of the type specifier Two common errors are use of a storage class other than register for a parameter declaration and using the storage class register for a global object declaration l format specifier not valid in Fmt FmtOut FmtFile Non Fatal Run time Error You can use the l format specifier only in Scan ScanOut and ScanFile l modifier is only valid with d i n o u and x specifiers Non Fatal Run time Error l format specifier is valid only for integer format specifiers L modifier is only valid with e f and g specifiers Non Fatal Run time Error L modifier which specifies that the argument is a long double can be used only in the floating point formats l modifier is only valid with e f g d i n o u and x specifiers Non Fatal Run time Error l format specifier is valid only for integer and real format specifiers Left operand of gt has incompatible type TYPE Compile Error Left operand of the gt dereference operation is either not a pointer to struct or union type or it is not a pointer type at all Left operand of has incompatible type TYPE Compile Error Left operand of the member selection operation must be a struct or union type Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 24 Monday March 9
272. s option enabled at all times The only penalty is a small delay each time you build or run the project By default LabWindows CVI does not unload and reload DLLs between each execution of your program This eliminates the delay in reloading the DLLs before each run It allows the DLLs to retain state information between each run If however you use a DLL that does not work correctly across multiple program executions enable the Reload DLLs Before Each Run option DLL Rules and Restrictions To call into a 16 bit DLL from LabWindows CVI 32 bit code you must observe the following rules and restrictions for DLL functions In the DLL header file change all references to int into references to short In the DLL header file change all references to unsigned or unsigned int to unsigned short You can declare the functions in the DLL as PASCAL or as CDECL You cannot use variable argument functions 00ProRef book 06chap04 fm Page 4 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues National Instruments Corporation 4 5 LabWindows CVI Programmer Reference Manual You can use the argument types char unsigned char int unsigned int short unsigned short long unsigned long float and double as well as pointers to any type and arrays of any type You can use typedefs for these types You can use the return types void char unsigned char int unsigned int short
273. s own ANSI C standard library Because of this you must use the external compiler s include files for the ANSI C library when compiling source files Although the include files for the other LabWindows CVI libraries are in the cvi include directory the LabWindows CVI ANSI C include files are in the cvi include ansi directory Thus you can specify cvi include as an include path in your external compiler while at the same time using the external compiler s version of the ANSI C include files Note Use the external compiler s ANSI C include files only when you compile a source file that you intend to link using the external compiler If you intend to link the file in LabWindows CVI use the LabWindows CVI ANSI C include files This is true regardless of which compiler you use to compile the source file For more information refer to the Setting Up Include Paths for LabWindows CVI ANSI C and SDK Libraries section later in this chapter Standard Input Output Window One effect of using the external compiler s ANSI C standard library is that the printf and scanf functions do not use the LabWindows CVI Standard Input Output window If you want to use printf and scanf you must create a console application which is called a character mode executable in Watcom You can continue to use the LabWindows CVI Standard Input Output Window by calling the FmtOut and ScanIn functions in the Formatting and I O library Resolving Callback References f
274. sel base base offset regs x ax 0x600 DPMI lock memory function regs x bx HIWORD base regs x cx LOWORD base regs x di LOWORD size 00ProRef book 06chap04 fm Page 5 Monday March 9 1998 3 23 PM Chapter 4 Windows 3 1 Compiler Linker Issues LabWindows CVI Programmer Reference Manual 4 6 National Instruments Corporation regs x si HIWORD size int86 0x31 amp regs amp regs return regs x cflag After the DMA is complete you must unlock the buffer You can unlock the buffer using the DPMILock function if you set regs x ax to 0x601 instead of 0x600 If you compile the DLL with the FPi or FPc switches or with no FP switches FPi is the default the DLL uses the WIN87EM DLL floating point emulator LabWindows CVI does not use WIN87EM DLL If the DLL uses WIN87EM DLL use the following strategy in the DLL to prevent conflicts 1 Structure the code so that all functions that perform any floating point math have known entry and exit points Ideally specify a particular set of exported entry points as the only ways into the floating point code 2 Call the Windows SDK function FPInit in each of these entry points Store the previous signal handler in a function pointer 3 If the DLL has its own exception handler call signal to register the DLL s own signal handler 4 Perform the floating point math 5 Upon exiting through one of the well defined DLL exit points call the
275. shown to the Libraries setting in the Windows Linking Switches dialog box clib3s math387 noemu387 Symantec C C Each object file must have the default library directive for the C library You must explicitly add the Symantec C library to your project The library filename is snn lib and it is in the lib subdirectory under the Symantec installation directory 00ProRef book 06chap03 fm Page 16 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 17 LabWindows CVI Programmer Reference Manual Borland Static versus Dynamic C Libraries When you link a Borland C C project that contains object or static library files you create in LabWindows CVI it is a good idea to configure the Borland project to use the static version of the Borland C libraries If you choose to use the dynamic C libraries you must compile the LabWindows CVI object modules with the _RTLDLL macro You must define the _RTLDLL macro in your source code before including any of the Borland C header files Borland Incremental Linker You cannot use your LabWindows CVI object or static library files in the Borland C compiler if you choose to use the incremental linker Turn off the Use Incremental Linker option Borland C Builder You cannot use your LabWindows CVI object or static library files in the Borland C Builder Watcom Pull in References The Watcom linker does not automatically link
276. sion you passed to the library function is invalid because you did not initialize it It is either a local variable or an object in dynamic memory that you did not initialize Uninitialized string Non Fatal Run time Error You never assigned a value to the pointer argument you passed to the library function or it is NULL union NAME declared inside parameter list has scope only for this declaration Compile Warning Union declared in the parameter list has scope only within the parameter list As a result its type is incompatible with all other types You should declare the union type before you declare function types that use it Unknown enumeration NAME Compile Error NAME is an undeclared enumeration type Unknown field NAME of TYPE Compile Error Member selection or dereference has attempted to access an undeclared member field name of a struct or union type Ensure that the member is declared for the struct or union type you select or dereference Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 43 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 44 National Instruments Corporation Unknown modifier Non Fatal Run time Error One of the modifiers in a format specifier is not valid Unknown or unsupported OMF record at position NUMBER OMF record type NUMBER Lo
277. sition NUMBER OMF record type NAME PC Windows Load Error OMF object file contains an unknown object record Make sure that the object file is OMF and conforms to the 32 bit format LabWindows CVI supports Bad relocation record encountered while reading external module FILE Link Error Object module is corrupted or is of a type that you cannot load into LabWindows CVI Bad OMF record at position NUMBER OMF record type NAME PC Windows Load Error OMF object file contains an unknown object record Make sure that the object file is OMF and conforms to the 32 bit format LabWindows CVI supports Byte ordering is invalid Non Fatal Run time Error Byte ordering that the o modifier specifies is not valid for the size of the integer The number of digits following the o must match the size of the integer and the digits must fall in the range zero to size of the integer 1 c modifier valid only with l format specifier Non Fatal Run time Error c modifier is only valid for the l format specifier The callback function NAME specified in the UIR file does not have required prototype Non Fatal Run time Error You specified the NAME function as a callback function for an item in a user interface resource file but it does not have the correct type to be a callback function Callback functions must have one of the callback types specified in the user interface library header The function will not be
278. situations 4 8 00ProRef book 11Index fm Page 14 Monday March 9 1998 3 23 PM Index National Instruments Corporation I 15 LabWindows CVI Programmer Reference Manual Windows 32 bit DLLs compatibility with external compilers bit fields 3 6 choosing compatible compiler 3 5 enum sizes 3 7 long doubles 3 7 returning floats and doubles 3 7 returning structures 3 7 structure packing 3 6 creating in LabWindows CVI 3 20 to 3 25 automatic inclusion of Type Library resource for Visual Basic 3 24 to 3 25 calling conventions for exported functions 3 21 to 3 22 customizing import library 3 20 to 3 21 exporting DLL functions and variables 3 22 export qualifier method 3 22 to 3 23 include file method 3 22 marking imported symbols in include file distributed with DLL 3 23 to 3 24 preparing source code 3 21 to 3 24 recommendations 3 24 DLL import library compatibility with external compilers 3 5 loading 3 1 to 3 4 16 bit DLLs not supported 3 2 default unloading reloading policy 3 4 DLL path pth files not supported 3 2 DllMain function 3 3 DLLs for instrument drivers and user libraries 3 2 generating import library 3 4 link errors when using DLL import libraries 3 2 releasing resources when DLL unloads 3 3 to 3 4 run state change callbacks in DLLs 3 2 to 3 3 using LoadExternalModule function 3 2 for standalone executables distributing 7 9 loading with LoadExternalModule 7 17 location 7 1
279. ss only the functions or variables that the DLL exports The DLL can export only globally declared functions and variables The DLL cannot export functions and variables you declare as static If you create your DLL in LabWindows CVI you can indicate which functions and variables to export in two ways the include file method and the qualifier method Include File Method You can use include files to identify symbols to export The include files must contain the declarations of the symbols you want to export The include files can contain nested include statements but the DLL does not export the declarations in the nested include files In the Create Dynamic Link Library dialog box you select from a list of all the include files in the project The include file method does not work with other compilers However it is similar to the def method that the other compilers use Export Qualifier Method You can mark each function and variable you want to export with an export qualifier Currently not all compilers recognize the same export qualifier names The most commonly used qualifier is __declspec dllexport Some also recognize __export LabWindows CVI recognizes both The cvidef h include file defines the DLLEXPORT 00ProRef book 06chap03 fm Page 22 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 23 LabWindows CVI Programmer Reference Manual macro to resolve di
280. st mark them with an import qualifier Variable declarations require import qualifiers so that the compiler can generate the correct code for accessing the variables You can use import qualifiers on function declarations but they are not necessary When you use an import qualifier on a function declaration external compilers can generate slightly more efficient code for calling the function Using import qualifiers in the include file you distribute with your DLL can cause problems if you use the same include file in the DLL source code If you mark variable declarations in the include file with import qualifiers and you use the include file in a source file other than the one in which you define the variable LabWindows CVI and the external compilers treat the variable as if it were imported from another DLL and generate incorrect code as a result If you use export qualifiers in the definition of symbols and the include file contains import qualifiers on the same symbols some external compilers report an error 00ProRef book 06chap03 fm Page 23 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 24 National Instruments Corporation You can solve these problems in several different ways You can avoid exporting variables from DLLs and thereby eliminate the need to use import qualifiers For each variable you want to export you can create func
281. stead of a obj file Calling InitCVIRTE and CloseCVIRTE If you link an executable or DLL in an external compiler you must call the InitCVIRTE function at the beginning of your main WinMain or DLLMain function For an executable using main as the entry point your code must include the following segment include lt cvirte h gt int main argc char argv if InitCVIRTE 0 argv 0 0 return 1 out of memory your other code For an executable using WinMain as the entry point your code must include the following segment include lt cvirte h gt int __stdcall WinMain HINSTANCE hInstance HINSTANCE hPrevInstance LPSTR lpszCmdLine int nCmdShow if InitCVIRTE hInstance 0 0 0 return 1 out of memory your other code 00ProRef book 06chap03 fm Page 14 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues National Instruments Corporation 3 15 LabWindows CVI Programmer Reference Manual For a DLL you also have to call CloseCVIRTE in DLLMain The code must include the following segment include lt cvirte h gt int __stdcall DllMain HINSTANCE hinstDLL DWORD fdwReason LPVOID pvReserved if fdwReason DLL_PROCESS_ATTACH if InitCVIRTE hinstDLL 0 0 0 return 0 out of memory your other ATTACH code else if fdwReason DLL_PROCESS_DETACH your other DETACH code CloseCVIRTE return 1 No
282. struments for technical support helps our applications engineers answer your questions more efficiently National Instruments Products Hardware revision _______________________________________________________________ Interrupt level of hardware _________________________________________________________ DMA channels of hardware ________________________________________________________ Base I O address of hardware _______________________________________________________ Programming choice _____________________________________________________________ National Instruments software ______________________________________________________ Other boards in system ____________________________________________________________ Base I O address of other boards ____________________________________________________ DMA channels of other boards _____________________________________________________ Interrupt level of other boards ______________________________________________________ Other Products Computer make and model ________________________________________________________ Microprocessor __________________________________________________________________ Clock frequency or speed __________________________________________________________ Type of video board installed _______________________________________________________ Operating system version __________________________________________________________ Operating system mode _______________
283. t LabWindows CVI has a callback mechanism you can use to inform a compiled module of changes in the program status To notify a compiled module of changes in the run state add a function with the name __RunStateChangeCallback to the compiled module LabWindows CVI automatically installs the callback for you The run state change callback must be in a compiled file not in a source file More than one compiled module can contain functions with this name because LabWindows CVI never enters it into the global name space The prototype for the callback is as follows void CVICALLBACK __RunStateChangeCallback int action libsupp h defines the actions in the following enumerated type enum kRunState_Start kRunState_Suspend kRunState_Resume kRunState_AbortingExecution kRunState_Stop 00ProRef book 06chap02 fm Page 4 Monday March 9 1998 3 23 PM Chapter 2 Using Loadable Compiled Modules National Instruments Corporation 2 5 LabWindows CVI Programmer Reference Manual kRunState_EnableCallbacks kRunState_DisableCallbacks The following examples show typical program state changes Example 1 kRunState_Start kRunState_EnableCallbacks user program execution begins a breakpoint or run time error occurs or user presses the Terminate Execution key combination kRunState_DisableCallbacks kRunState_Suspend program execution suspends CVI environment resumes user requests the execut
284. t as in the LabWindows CVI development environment Refer to Chapter 1 Configuring LabWindows CVI in the LabWindows CVI User Manual for more information on DSTRules UNIX Options The LabWindows CVI Run time Engine recognizes the activate appFont dialogFont editorFont menuFont messageBoxFont useDefaultColors useMetaKey and warpMouseOverDialogBoxes options under UNIX platforms They have the same effect as in the LabWindows CVI development environment Refer to Chapter 1 Configuring LabWindows CVI in the LabWindows CVI User Manual for more information on these options 00ProRef book 06chap07 fm Page 7 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 8 National Instruments Corporation Necessary Files for Running Executable Programs In order for your executable to run successfully on a target computer all files the executable requires must be accessible Your final distribution kit must contain all the necessary files to install your LabWindows CVI executable program on a target machine as shown in Figure 7 1 Figure 7 1 Files Necessary to Run a LabWindows CVI Executable Program on a Target Machine Executable This file contains a precompiled prelinked version of your LabWindows CVI project and any instrument driver program files that you link to your project It also contains the application name and icon resource to
285. t causes the error or the type of invalid pointer involved Pointer Arithmetic Non Fatal Pointer arithmetic expressions involve a pointer sub expression and an integer sub expression LabWindows CVI generates an error when the pointer sub expression is 00ProRef book 06chap01 fm Page 8 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 9 LabWindows CVI Programmer Reference Manual invalid or when the arithmetic operation results in an invalid pointer expression The following user protection errors involve pointer arithmetic Pointer arithmetic involving uninitialized pointer Pointer arithmetic involving null pointer Out of bounds pointer arithmetic calculation of an array address that results in a pointer value either before the start or past the end of the array Pointer arithmetic involving pointer to freed memory Pointer arithmetic involving invalid pointer Pointer arithmetic involving address of non array object Pointer arithmetic involving pointer to function Array index too large Negative array index Pointer Assignment Non Fatal LabWindows CVI generates pointer assignment errors when you assign invalid values to pointer variables These warnings can help determine when a particular pointer becomes invalid The following user protection errors involve pointer assignment Assignment of uninitialized poin
286. t compilers design the Application Programming Interface API for your DLL to avoid such problems The following are areas in which the DLLs that external compilers create are not fully compatible 00ProRef book 06chap03 fm Page 5 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 6 National Instruments Corporation Structure Packing The compilers differ in their default maximum alignment of elements within structures If your DLL API uses structures you can guarantee compatibility among the different compilers by using the pack pragma to specify a specific maximum alignment factor Place this pragma in the DLL include file before the definitions of the structures You can choose any alignment factor After the structure definitions reset the maximum alignment factor back to the default as in the following example pragma pack 4 set maximum alignment to 4 typedef struct char a int b MyStruct1 typdef struct char a double b MyStruct2 pragma pack reset max alignment to default LabWindows CVI predefines the __DEFALIGN macro to the default structure alignment of the current compatible compiler Bit Fields Borland C C uses the smallest number of bytes necessary to hold the bit fields you specify in a structure The other compilers always use 4 byte elements You can force compatibility by adding a dummy bit fiel
287. t numbers B 2 Fax on Demand support B 1 files for running standalone executables accessing UIR image and panel state files 7 12 DLL files Windows 3 1 7 13 to 7 14 Windows 95 NT 7 13 loading files using LoadExternalModule 7 14 to 7 18 DLL files and DLL path files Windows 3 1 7 17 to 7 18 DLL files Windows 95 NT 7 17 files in project 7 15 to 7 16 forcing referenced modules into executable or DLL 7 15 library files not in project 7 16 object files not in project 7 16 other types of files 7 19 source files 7 18 location of files on target machine 7 9 to 7 19 relative pathnames for accessing files 7 19 required files 7 8 to 7 9 floats returning 3 7 fonts multiplatform application considerations 6 3 Windows 95 NT files for standalone executables 7 11 Formatting and I O Library 9 6 to 9 7 forward lt delete gt key multiplatform application considerations 6 3 FP Auto Load List command Edit menu 8 2 FTP support B 1 functions exported by ordinal value only 4 20 G general protection errors 1 11 Generate DLL Glue Code command Options menu 4 8 4 9 Generate DLL Glue Object command Options menu 7 17 Generate DLL Import Library command Options menu 3 4 3 5 Generate DLL Import Source command Options menu 3 21 Generate Windows Help command Options menu 3 25 GetCVIWindowHandle function 4 21 glue code See Windows 16 bit DLLs GNU C Compiler 5 3 GPIB GPIB 488 2 Library 9 4 to 9 5 graphica
288. table The pth file must have the same base name as the file you passed to LoadExternalModule If the pth file contains an absolute path to the DLL use that path to find the DLL If the pth file contains a simple filename use the standard Windows DLL search algorithm directory of executables 00ProRef book 06chap07 fm Page 17 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs LabWindows CVI Programmer Reference Manual 7 18 National Instruments Corporation current working directory windows windows system then the PATH environment variable 2 Look for a dll file in the directory of the executable The dll file must have the same base name as the file you passed to LoadExternalModule 3 Otherwise use the standard Windows DLL search algorithm If you maintain the DLL glue object module as a separate file from the executable you must pass LoadExternalModule a pathname to the DLL glue object module and it uses the following search method to find the DLL 1 Look for a pth file that is in the same directory as the DLL glue object module and that has the same base name as the DLL glue object module If the pth file contains an absolute path to the DLL use it to find the DLL If the pth file contains a simple filename use the standard Windows DLL search algorithm 2 Look for a dll file that is in the same directory as the DLL glue object module and that has the sam
289. te It is harmless but unnecessary to call these functions when you link your executable in LabWindows CVI for Windows 95 NT Watcom Stack Based Calling Convention When you use the LabWindows CVI libraries in the Watcom compiler you must set the default calling convention to the 80486 Stack Based calling convention In the command line compiler this is the 4s option In the Watcom IDE you can set the default calling convention by using the Options C Compiler Switches command The option is in the Target Processor section of the Memory Model and Processor Switches section of the dialog box If you do not set this option the Watcom linker reports undefined references to the LabWindows CVI run time libraries Using Object and Library Files in External Compilers When you use an external compiler to link a project that contains object or static library files created in LabWindows CVI keep several points in mind Default Library Directives Most compilers insert default library directives in the object and library files they generate A default library directive tells the linker to automatically include a named library in the link Normally the directive refers to the name of C library files If no files in the link contain a 00ProRef book 06chap03 fm Page 15 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 16 National Instruments Corporation default lib
290. ter value Assignment of out of bounds pointer expression assignment of an address before the start or past the last element of an array Assignment of pointer to freed memory Assignment of invalid pointer expression Pointer Dereference Errors Fatal Dereferencing of invalid pointer values is a fatal error because it can cause a memory fault or other serious problem The following user protection errors involve pointer dereferencing Dereference of uninitialized pointer Dereference of null pointer Dereference of out of bounds pointer dereference using a pointer value before the start or past the end of an array Dereference of pointer to freed memory Dereference of invalid pointer expression Dereference of data pointer for use as a function Dereference of function pointer for use as data 00ProRef book 06chap01 fm Page 9 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler LabWindows CVI Programmer Reference Manual 1 10 National Instruments Corporation Dereference of a pointer to an n byte type where less than n bytes exist in the object Dereference of unaligned pointer UNIX only Pointer Comparison Non Fatal LabWindows CVI generates pointer comparison errors for erroneous pointer comparison expressions The following user protection errors involve pointer comparison Comparison involving uninitialized pointer Comp
291. that you apply implicitly or explicitly to the void values you obtain from malloc or calloc do not disable user protection Casting a pointer to one arithmetic type to a pointer to a different one such as int unsigned short and so on does not affect run time checking on the resulting pointer nor does casting a pointer to a void pointer void 00ProRef book 06chap01 fm Page 14 Monday March 9 1998 3 23 PM Chapter 1 LabWindows CVI Compiler National Instruments Corporation 1 15 LabWindows CVI Programmer Reference Manual Dynamic Memory LabWindows CVI provides run time error checking for pointers and arrays in dynamically allocated memory You can use the ANSI C library functions malloc or calloc to allocate dynamic memory These functions return void values that you must cast to some other type before the memory can be used During program execution LabWindows CVI uses the first such cast on the return value of each call to these functions to determine the type of the object that will be stored in the dynamic memory Subsequent casts to different types can disable checking on the dynamic data as explained in the Pointer Casting discussion in this section You can use the realloc function to resize dynamically allocated memory This function increases or decreases the size of the object associated with the dynamic memory LabWindows CVI adjusts the user protection information accordingly Avoid Unassigned Dy
292. the executable or from previously loaded run time modules A table of these symbols must be available in the executable When you link your program in LabWindows CVI LabWindows CVI automatically includes a symbol table This is true whether you run your program in the LabWindows CVI development environment or as a standalone executable When you link your program in an external compiler the external compiler does not make such a table available to the Utility Library LabWindows CVI provides ways to help you create the symbol table easily Resolving References to the LabWindows CVI Run Time Engine LabWindows CVI makes available two object files that contain symbol table information for the LabWindows CVI libraries that are in Run time Engine DLLs Include cvi extlib refsym obj in your external compiler project if your run time modules refer to any symbols in the User Interface Formatting and I O RS 232 DDE TCP or Utility Library Include cvi extlib arefsym obj in your external compiler project if your run time modules refer to any symbols in the ANSI C library If you have to use this object file and you use Borland C C to create your executable you must choose Static Linking for the Standard Libraries In the Borland C C IDE you can do this in the New Target and Target Expert dialog boxes Resolving References to Symbols Not in Run Time Engine If your run time modules refer to any other symbols from your executable y
293. the project When you modify and save any of these uir files LabWindows CVI regenerates the object file to reflect the changes 4 Include this object file in the external compiler project you use to create the executable 5 You must call InitCVIRTE at the beginning of your main or WinMain function Refer to the Calling InitCVIRTE and CloseCVIRTE section later in this chapter Linking to Callback Functions Not Exported from a DLL Normally the User Interface Library searches for callback functions only in the table of functions in the executable When you load a panel or menu bar from a DLL you might want to link to non static callback functions the DLL contains but does not export You can do this by calling LoadPanelEx and LoadMenuBarEx When you pass the DLL module handle to LoadPanelEx and LoadMenuBarEx the User Interface Library searches the table of callback functions the DLL contains before searching the table that the executable contains Refer to Chapter 4 User Interface Library Function Reference of the LabWindows CVI User Interface Reference Manual for detailed information on LoadPanelEx and LoadMenuBarEx If you create your DLL in LabWindows CVI LabWindows CVI includes the table of functions in the DLL automatically If you create your DLL using an external compiler you must generate an object file that contains the necessary table as follows 1 Create a LabWindows CVI project that contains the uir files your DLL loads
294. time Engine automatically sets the required configuration options for you Refer to the How to Set the Configuration Options discussion in Chapter 1 Configuring LabWindows CVI of the LabWindows CVI User Manual for detailed instructions on how to manually set configuration options on each platform for the LabWindows CVI development environment Under UNIX you set the Run time Engine configuration options in the same manner Under Windows you set the Run time Engine configuration options in a similar manner but with the following differences Under Windows 95 NT set the configuration options in the Registry under the following key HKEY_LOCAL_MACHINE Software National Instruments CVI Run Time Engine cvirte Under Windows 3 1 set the configuration options in the cvirtn section of the win ini file where n is the version of the Run time Engine Note Under UNIX changes to options do not take effect until you restart your X server or issue the xrdb Xdefaults command cvirtx Windows 3 1 Only Because executables load and execute the Run time Engine under Windows 3 1 they must be able to locate the Run time Engine on the hard disk Under Windows 3 1 executables find the Run time Engine using cvirtn where n is the version number of the Run time Engine configuration option Assign the pathname of the Run time Engine executable file to the cvirtn option in the cvirtn section of win ini as in the following example c
295. tion LabWindows CVI and other linkers resolve all definitions to the same variable If you want separate variables use different names or the static keyword If you want one variable change all definitions except one to extern declarations Link Error In Borland mode multiple modules must not contain uninitialized definitions of the same global variable Borland creates a separate variable for each definition LabWindows CVI and other linkers resolve all definitions to the same variable If you want separate variables use different names or the static keyword If you want one variable change all definitions except one to extern declarations Symbol NAME exported from header FILE not found in DLL DLL Link Error or Import Library Creation Error When you used the Include File method for specifying the symbols to export from a DLL one of the symbols you declared in the include file was not in the DLL project Or when you created import libraries from an include file and a DLL one of the symbols you declared in the include file was not in the DLL Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 38 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings National Instruments Corporation A 39 LabWindows CVI Programmer Reference Manual Syntax error found TOKEN1 expecting TOKEN2 Compile Error Syntax error occurred because
296. tions to get and set its value or a function to return a pointer to the variable You do not have to use import qualifiers for functions This is the simplest approach and works in LabWindows CVI However it does not work if you use an export qualifier in a function definition and you create the DLL with an external compiler that requires the declaration to use the same qualifier You can create a separate include file for distribution with the DLL You can use a special macro that resolves to either an import or export qualifier depending on a conditional compilation flag In LabWindows CVI you can set the flag in your DLL project by using the Compiler Defines command in the Options menu of the Project window Recommendations To make creating a DLL as simple as possible adhere to the following recommendations Use the DLLSTDCALL macro in the declaration and definition of all functions you want to export Do not export functions with a variable number of arguments Identify the symbols you want to export using the include file method Do not use export qualifiers If you use an external compiler use the def file method Do not export variables from the DLL For each variable you want to export create functions to get and set its value or a function to return a pointer to the variable Do not use import qualifiers in the include file If you follow these recommendations you reap the following benefits
297. to freed memory Non Fatal Run time Error One of the pointer expressions in the comparison is invalid because it refers to a location in dynamic memory that you deallocated with the free function Once you free the memory all pointers into that block of memory become invalid Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm Page 9 Monday March 9 1998 3 23 PM Appendix A Errors and Warnings LabWindows CVI Programmer Reference Manual A 10 National Instruments Corporation Compound statements nested too deeply Compile Error Program has exceeded the compiler limitations on the number of nested compound statements reduce the depth of the nested compound statements in the program Conditional inclusion nested too deeply Compile Error Program has exceeded the compiler limitations on the number of nested conditional preprocessor directives reduce the depth of the conditional preprocessor directives nested in the program Conflicting GRPDEFs group name NAME Link Error Object module is probably corrupted Conflicting argument declarations for function FUNCTION Compile Error Arguments of the named function prototype declaration do not match those for the old style function definition of the same name ensure that the function declaration matches that of the old style function definition A better course is to change the old style function def
298. to use your DLL you can use the __cdecl or Watcom stack based calling convention to declare the functions you want to export If however you want your DLL to be callable from environments such as Microsoft Visual Basic you must declare the functions you want to export with the __stdcall calling convention You must do this by explicitly defining the functions with the __stdcall keyword This is true whether or not you choose to make __stdcall the default calling convention for your 00ProRef book 06chap03 fm Page 21 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 22 National Instruments Corporation project You must use the __stdcall keyword in the declarations in the include file you distribute with the DLL Other platforms such as UNIX or Windows 3 1 do not recognize the __stdcall keyword If you work with source code that you might use on other platforms you must use a macro in place of __stdcall The cvidef h include file defines the DLLSTDCALL macro for this purpose The following are examples of using the DLLSTDCALL macro int DLLSTDCALL MyIntFunc void char DLLSTDCALL MyStringFunc void Note You cannot use the __stdcall calling convention on functions with a variable number of arguments Consequently you cannot use such functions in Microsoft Visual Basic Exporting DLL Functions and Variables When a program uses a DLL it can acce
299. u use the modini or modreg program to modify cvi ini or the Registry If LabWindows CVI is running while you use these programs you will lose your changes 00ProRef book 06chap08 fm Page 3 Monday March 9 1998 3 23 PM National Instruments Corporation 9 1 LabWindows CVI Programmer Reference Manual 9 Checking for Errors in LabWindows CVI This chapter describes LabWindows CVI error checking and how LabWindows CVI reports errors in LabWindows CVI libraries and compiled external modules When you develop applications in LabWindows CVI you usually have debugging and the Break on Library Errors option enabled With these features enabled LabWindows CVI identifies and reports programming errors in your source code Therefore you might have a tendency to relax your own error checking However in compiled modules and standalone executables debugging and the Break on Library Errors are disabled This results in smaller and faster code but you must perform your own error checking This fact is important to remember because many problems can occur in compiled modules and standalone executables even if the program works inside the environment It is important to check for errors that can occur because of external factors beyond the control of your program Examples include running out of memory or trying to read from a file that does not exist malloc fopen and LoadPanel are examples of functions that can encounter such errors You m
300. uch as AnyType e S SDK Windows Software Development Kit An API in the Windows operating system scroll bars Areas along the bottom and right sides of a window that show your relative position in the file You can use scroll bars can be used to move about in the window scrollable text box A dialog box item that displays text in a scrollable display select To choose the item that the next executed action affects by moving the input focus highlight to a particular item or area shortcut key command A combination of keystrokes that provide a means of executing a command without accessing a menu in the command bar slide control A function panel control that resembles a physical slide switch A slide control is a means for selecting one item from a list of options it inserts a value in a function call that depends upon the position of the cross bar on the switch slider The cross bar on the slide control that determines the value placed in the function call Source window A LabWindows CVI work area where you edit and execute programs 00ProRef book 10gloss fm Page 6 Monday March 9 1998 3 23 PM Glossary National Instruments Corporation G 7 LabWindows CVI Programmer Reference Manual Standard Input Output window A LabWindows CVI work area in which textual output to and input from the user take place standard libraries The LabWindows CVI User Interface Analysis Data Formatting and I O GPIB GPIB 488
301. ucture packing pragma Windows 1 4 to 1 5 C library issues 1 5 C style comment markers 1 4 callback functions compiled modules using asynchronous callbacks 2 7 direct callback by DLLs 4 12 to 4 15 notification of run state changes in compiled modules 2 4 to 2 5 using in DLLs 2 6 to 2 7 callback references resolving Windows 95 NT from modules loaded at run time 3 12 references to non LabWindows CVI symbols 3 12 to 3 13 run time module references to symbols not exported from DLL 3 13 from uir files 3 10 to 3 12 linking to callback functions not exported from DLL 3 11 to 3 12 calling conventions Windows 95 NT for exported functions 3 21 to 3 22 using qualifiers 1 2 to 1 3 casting See pointer casting cdecl calling convention 1 2 _cdecl calling convention qualifier 1 2 __cdecl calling convention qualifier 1 3 Check Disk Dates Before Each Run option 4 4 CloseCVIRTE function 3 14 to 3 15 code See source files colors multiplatform application considerations 6 3 comment markers C style 1 4 compiled modules See loadable compiled modules compiler See also compiler options C library issues 1 5 using low level I O functions 1 5 compiler defines 1 2 compiler limits table 1 1 00ProRef book 11Index fm Page 2 Monday March 9 1998 3 23 PM Index National Instruments Corporation I 3 LabWindows CVI Programmer Reference Manual data types allowable data types table 1 6 converting 16
302. ules for Accessing UIR Image and Panel State Files on All Platforms 7 12 Rules for Using DLL Files under Windows 95 NT 7 13 Rules for Using DLL Files under Windows 3 1 7 13 Rules for Loading Files Using LoadExternalModule 7 14 Forcing Modules that External Modules Refer to into Your Executable or DLL 7 15 Using LoadExternalModule on Files in the Project 7 15 Using LoadExternalModule on Library and Object Files Not in the Project 7 16 Using LoadExternalModule on DLL Files under Windows 95 NT 7 17 Using LoadExternalModule on DLL and Path Files under Windows 3 1 7 17 Using LoadExternalModule on Source Files c 7 18 Rules for Accessing Other Files 7 19 Error Checking in Your Standalone Executable or DLL 7 19 Chapter 8 Distributing Libraries and Function Panels How to Distribute Libraries 8 1
303. ult of a previous invalid pointer operation Assignment of out of bounds pointer NUMBER bytes before start of array Non Fatal Run time Error Value you assigned to the pointer refers to an invalid location which is NUMBER bytes before an array The right side of the assignment is probably the result of previous illegal pointer arithmetic Assignment of out of bounds pointer NUMBER bytes past end of array Non Fatal Run time Error Value you assigned to the pointer refers to an invalid location which is NUMBER bytes past the end of an array The right side of the assignment is probably the result of previous illegal pointer arithmetic Assignment of pointer to freed memory Non Fatal Run time Error Value you assigned to the pointer is invalid because it refers to a location in dynamic memory that the free function deallocated After memory is free all pointers into that block of memory are invalid Assignment of uninitialized pointer value Non Fatal Run time Error Value you assigned to the pointer is invalid because it was not initialized The right side of the assignment is probably an uninitialized local variable or an object in dynamic memory that you allocated with malloc Initialize local variables and dynamic memory before you use them calloc both allocates and initializes dynamic memory Table A 1 Error Messages Continued Error Message Type Error Comment 00ProRef book 07AppA fm P
304. unctions are portable to Windows if you include lowlvlio h in your Windows application In general the ANSI C User Interface Analysis Formatting and I O Utility GPIB VXI RS 232 and TCP libraries are portable across platforms However a few functions are not multi platform The majority of these functions are in the Utility Library The documentation and function panels for the non portable functions contain notes that list the platforms to which they apply Only LabWindows CVI for Windows has DDE Data Acquisition and Easy I O for DAQ libraries The X Property Library is available only under UNIX The ActiveX Automation Library is available only under Windows 95 NT Although LabWindows CVI provides the TCP Library on all platforms you are responsible for ensuring that the system has hardware and software support for the TCP server Various processor architectures store integers and floating point numbers in different byte order To circumvent these inconsistencies use the o modifier in the Formatting and I O Library to describe the byte ordering of device data In a Fmt Scan function use the o modifier to describe the byte ordering for the buffer that contains the raw device data Do not use the o modifier on the buffer that holds the data in the byte ordering of the host processor For example if you use a GPIB instrument that sends two byte binary data in Intel byte order use the following code short instr_buf 100 short
305. unsigned short long and unsigned long as well as pointers to any type You can use typedefs for these types You can use the return types float and double only if the DLL is created with a Microsoft C compiler and the functions returning floats or double are declared with the cdecl calling convention You do not have to modify the glue code generated for functions that return float or double values In the DLL header file enum sizes must be consistent between LabWindows CVI and the compiler for the DLL typedef enum No_Error Device_Busy Device_Not_Found ErrorType The size of ErrorType is 2 bytes in Visual C whereas it is 1 byte in LabWindows CVI To force LabWindows CVI to treat ErrorType as 2 bytes add another enum value explicitly initialized to a 2 byte value such as the following ErrorType_Dummy 32767 If the DLL you are using performs DMA on a buffer you pass to it you might experience a problem The DLL might attempt to lock the buffer in memory by calling the Windows SDK function GlobalPageLock GlobalPageLock fails on buffers allocated with the Watcom malloc function that LabWindows CVI uses in 32 bit mode Write the DLL so that if GlobalPageLock fails the DLL attempts to lock the buffer with the following code int DPMILock void buffer unsigned long size DWORD base unsigned sel offset union _REGS regs sel SELECTOROF buffer offset OFFSETOF buffer base GetSelectorBase
306. uration forms from their user manuals Include additional pages if necessary Name __________________________________________________________________________ Company _______________________________________________________________________ Address ________________________________________________________________________ _______________________________________________________________________________ Fax ___ ________________Phone ___ __________________________________________ Computer brand____________ Model ___________________Processor _____________________ Operating system include version number ____________________________________________ Clock speed ______MHz RAM _____MB Display adapter __________________________ Mouse ___yes ___no Other adapters installed_______________________________________ Hard disk capacity _____MB Brand_________________________________________________ Instruments used _________________________________________________________________ _______________________________________________________________________________ National Instruments hardware product model _____________ Revision ____________________ Configuration ___________________________________________________________________ National Instruments software product ___________________ Version _____________________ Configuration ___________________________________________________________________ The problem is ________________________________
307. us information through a global variable called rs232err If this variable is negative after the function returns an error occurred Notice that many of the functions return a value in addition to setting the global variable Usually this value contains information on the result of the function that can also be used to detect a problem Each function should be checked individually Refer to the RS 232 section in the LabWindows CVI Standard Libraries Reference Manual or the function panel help for a listing of the error codes and information on the individual functions You can use GetRS232ErrorString to get the error message associated with each RS 232 Library error code Note If your program uses multiple threads use the ReturnRS232Err function in place of the rs232err global variable VISA Library The VISA Library functions return a negative value when they detect an error They return a positive value as a warning when they can complete their task but not in the way you might expect This library uses a common set of error and warning codes but the warning code values are entirely separate from the error code values The error codes always contain 0xBFFF in the upper two bytes The warning codes always contain 0x3FFF in the upper two bytes Refer to the NI VISA Programmer Reference Manual or the function panel help for a listing of the error and warning codes and information on the individual functions You can use viStatusDesc to obtain the er
308. uses the signed integer definition to make LabWindows CVI compatible with the Sun Solaris header files LabWindows CVI for Solaris 1 uses the Sun Solaris version of the ANSI function strftime which incorrectly interprets the W control string as the one based week number instead of the zero based week number as ANSI specifies In LabWindows CVI for Solaris 1 ungetc works improperly in certain cases fsetpos fails to erase all memory of pushback characters by ungetc ungetc does not clear the end of file indicator on success ungetc fails in certain cases after reading to the end of a file In LabWindows CVI for Solaris 1 signal handlers you install with the signal function remain installed after invocation of the handler The ANSI standard specifies that these handlers be removed before they are invoked In standalone executables LabWindows CVI creates for Solaris 1 the function abort and the macro assert do not terminate the program if you install a signal handler for the SIGABRT signal and the handler returns rather than calling longjmp The ANSI standard specifies that the program terminate in these cases Under some versions of Sun Solaris 2 for example Solaris 2 5 the ANSI function setlocale does not work properly when running programs in the LabWindows CVI development environment LabWindows CVI links programs in the development environment to the Sun Solaris static library libc a which contains
309. ust provide your own error checking for these types of functions Other functions return errors only if your program is incorrect The following function call returns an error only if pnl or ctrl is invalid SetCtrlAttribute pnl ctrl ATTR_DIMMED FALSE The Break on Library Errors feature of LabWindows CVI adequately checks for these types of errors while you develop your program and external factors do not affect this function call Therefore it is generally not necessary to perform explicit error checking on this type of function call One method of error checking is to check the status of function calls upon their completion Most functions in commercial libraries return errors when they encounter problems LabWindows CVI libraries are no exception All the functions in the LabWindows CVI libraries and in the instrument drivers available from National Instruments return a status code to indicate the success or failure of execution These codes help you determine the problem when the program does not run as you expected it to This chapter describes how LabWindows CVI reports these status codes and some techniques for checking them 00ProRef book 06chap09 fm Page 1 Monday March 9 1998 3 23 PM Chapter 9 Checking for Errors in LabWindows CVI LabWindows CVI Programmer Reference Manual 9 2 National Instruments Corporation Note Status codes are integer values These values are either common to an entire library of functions or sp
310. ution and Standard Input Output windows Create Object File command 3 26 Generate DLL Glue Code command 4 8 4 9 Generate DLL Glue Object command 7 17 Generate DLL Import Library command 3 4 3 5 Generate DLL Import Source command 3 21 ordinal value for exporting functions 4 20 P pack pragma Windows 1 4 to 1 5 3 6 panel state files accessing from standalone executables 7 12 required for standalone executables 7 9 pascal Pascal and _pascal keywords 1 2 Pascal DLL functions 4 8 4 9 path files See pth files PCX files multiplatform application considerations 6 3 platform independent applications building See multiplatform applications building plock function UNIX 5 7 pointer casting 1 14 pointer protection errors 1 8 to 1 10 disabling for individual pointers 1 12 to 1 13 dynamic memory protection errors 1 11 pointer arithmetic non fatal 1 8 to 1 9 pointer assignment non fatal 1 9 pointer casting non fatal 1 10 pointer comparison non fatal 1 10 pointer dereference errors fatal 1 9 to 1 10 pointer subtraction non fatal 1 10 pointers DLLs passing pointers that point to other pointers 4 18 to 4 20 returned by DLLs 4 15 to 4 17 pragmas disabling or enabling library protection errors 1 13 to 1 14 structure packing Windows 1 4 to 1 5 3 6 predefined macros 6 1 printf function LabWindows CVI implementation 5 4 using with external compiler 3 10 process segments locking into
311. virt5 cvrt5 c windows system cvirt5 cvirt5 exe 00ProRef book 06chap07 fm Page 6 Monday March 9 1998 3 23 PM Chapter 7 Creating and Distributing Standalone Executables and DLLs National Instruments Corporation 7 7 LabWindows CVI Programmer Reference Manual cvidir Windows Only Under Windows 95 NT cvidir specifies the location of the directory that contains the bin and fonts subdirectories that the Run time Engine requires This Registry entry is necessary to enable the Windows 95 NT Run time Engine DLL to load When you install the LabWindows CVI Run time Engine under Windows 95 NT the installation program places the bin and fonts subdirectories in the cvirte directory under the Windows system directory The installation program also creates the cvidir entry in the Registry For Windows 3 1 set the cvidir option only if the Run time Engine resides in a directory other than the directory that contains the bin and fonts subdirectories Set it to the directory that contains the bin and fonts subdirectories useDefaultTimer Windows Only The LabWindows CVI Run time Engine recognizes the UseDefaultTimer option under Windows platforms It has the same effect as in the LabWindows CVI development environment Refer to Chapter 1 Configuring LabWindows CVI in the LabWindows CVI User Manual for more information on useDefaultTimer DSTRules The LabWindows CVI Run time Engine recognizes the DSTRules option It has the same effec
312. xit 1 Status Reporting by LabWindows CVI Libraries and Instrument Drivers This section describes how LabWindows CVI libraries and instrument drivers report errors Notice that libraries that return their status code using global variables or separate functions sometimes report additional status information through return values User Interface Library The User Interface Library routines return a negative value when they detect an error Some functions such as LoadPanel return positive values for a successful completion This library uses a common set of error codes which the LabWindows CVI User Interface Reference Manual and the function panel help list You can use the function GetUILErrorString to get the error message associated with each User Interface Library error code Analysis Advanced Analysis Libraries The Analysis and Advanced Analysis Library functions return a negative value when they detect an error This library uses a common set of error codes which the LabWindows CVI Standard Libraries Reference Manual the LabWindows CVI Advanced Analysis Reference Manual and the function panel help list You can use the function GetAnalysisErrorString to get the error message associated with each Analysis Library error code 00ProRef book 06chap09 fm Page 3 Monday March 9 1998 3 23 PM Chapter 9 Checking for Errors in LabWindows CVI LabWindows CVI Programmer Reference Manual 9 4 National Instruments Corporation
313. y project LabWindows CVI includes all object modules from the lib in the static library it creates When you create an executable or DLL LabWindows CVI uses only the necessary modules from the lib file Note Do not set the default calling convention to __stdcall if you want to create a static library for all four compatible external compilers 00ProRef book 06chap03 fm Page 25 Monday March 9 1998 3 23 PM Chapter 3 Windows 95 NT Compiler Linker Issues LabWindows CVI Programmer Reference Manual 3 26 National Instruments Corporation Creating Object Files in LabWindows CVI You can create an object file in LabWindows CVI in one of two ways Include a source c file in your project Enable the Compile into Object option for the source file by double clicking in the space next to the filename in the Project window under the column marked O Compile the file Open a source c file and select the Create Object File command in the Options menu of the Source window In LabWindows CVI for Windows 95 NT you can choose to create an object file for only the currently selected compiler or to create object files for all four compatible external compilers Note Do not set the default calling convention to __stdcall if you want to create a static object for all four compatible external compilers Calling Windows SDK Functions in LabWindows CVI You can call Windows SDK Functions in LabWindows CVI for Windows 95 NT
314. y protection errors report illegal operations with dynamic memory and corrupted dynamic memory during allocation and deallocation Memory Deallocation Non Fatal LabWindows CVI generates memory deallocation errors when the pointer is not the result of a memory allocation The following user protection errors involve memory deallocation Attempt to free uninitialized pointer Attempt to free pointer to freed memory Attempt to free invalid pointer expression Attempt to free pointer not allocated with malloc or calloc Memory Corruption Fatal LabWindows CVI generates memory corruption errors when a memory allocation deallocation detects corrupted memory During each dynamic memory operation LabWindows CVI verifies the integrity of the memory blocks it uses in the operation When you set the Debugging Level to Extended LabWindows CVI thoroughly checks all dynamic memory on each memory operation LabWindows CVI generates the following error when it discovers a problem Dynamic memory is corrupt General Protection Errors LabWindows CVI also checks for stack overflow and missing return values Stack overflow fatal Missing return value non fatal The missing return value error means that a non void function one you do not declare with void return type returned but did not returned a value Library Protection Errors Library functions sometimes generate errors when they receive invalid argument

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