Using .exp file with 3rd party dll.

[J Ahn]

I'm new to programming in Labwindows, and could use some help.  I'm having problems using a 3rd party dll.  The dll comes with both a .lib and an .exp file.  When I write a Visual C++ program using the dll, I get  "undefined symbol" errors if I only use the .lib file.  If I add both to my project, the program compiles fine.

For Labwindows V5, I also get the "undefined symbol" errors when I include the .lib file only.  Is there any way to add the .exp file or to not use it at all for Labwindows?  I did try to create a .lib file for the dll using Labwindows, but the dll uses another dll, which Labwindows gives an error message for in the .h file.  Thanks.

[rolfk]

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@J Ahn wrote:

I'm new to programming in Labwindows, and could use some help.  I'm having problems using a 3rd party dll.  The dll comes with both a .lib and an .exp file.  When I write a Visual C++ program using the dll, I get  "undefined symbol" errors if I only use the .lib file.  If I add both to my project, the program compiles fine.

For Labwindows V5, I also get the "undefined symbol" errors when I include the .lib file only.  Is there any way to add the .exp file or to not use it at all for Labwindows?  I did try to create a .lib file for the dll using Labwindows, but the dll uses another dll, which Labwindows gives an error message for in the .h file.  Thanks.

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Mmh, haven't dealt recently with CVI myself, but the .exp file is just the binary form for Microsoft C of what usually has been put in a .def file. The prefered way nowadays in Visual C (of course not compatible with other compilers other than maybe LabWindows CVI) is however to simply declare the function name with __declspec(dllexport) and that should take care of this. GNU compilers typically use something like attribute(export) instead.

Rolf Kalbermatter

[J Ahn]

Actually I think I figured out my problem.  It looks like the functions in the dll were mangled.  I was able to get around it by building a new dll with this dll in Visual C++ and by using the below:

#ifdef __cplusplus
extern "C" {
#endif
__declspec(dllexport) int __stdcall Array_Add(int *array, int num);
#ifdef __cplusplus
}
#endif

It worked for a couple of functions so we'll see how it goes.

[mvr]

It sure sounds like you found the solution.  Here is a link that describes the same fix. http://digital.ni.com/public.nsf/websearch/862567530005F09C862566D600768A51?OpenDocument

The disadvantage from the point of visual c++ is that you cannot overload a function when using the extern c declaration. 

For anyone who comes across this thread later, this link provides a way to check if you have a dll that uses name mangling.

http://forums.ni.com/ni/board/message?board.id=180&message.id=11323&requireLogin=False