You are now ready to use or debug your DLL from LabVIEW. Select Build» Build to compile and link your DLL. Once you write the code, declare what functions to export, and set the calling conventions, you are ready to build your DLL. def file method to export stdcall functions.

Therefore, NI recommends that you use the . def file method of exporting functions, rather than the _declspec(dllexport) method. When using standard calling conventions, the function name is decorated in the DLL. Int _stdcall GetSphereSAandVol(doublt radius, double* sa, double* vol) To specify standard calling conventions, place the _stdcall keyword in the function declaration and definition:Įxtern 'C' int _stdcall GetSphereSAandVol(double radius, double* sa, double* vol) _declspec(dllexport) int _cdecl GetSphereSAandVol(doublt radius, double* sa, double* vol) If you want to explicitly declare the function as a C call, use the _cdecl keyword in the function declaration and definition:Įxtern 'C' _declspec(dllexport) int _cdecl GetSphereSAandVol(double radius, double* sa, double* vol) This is the default unless you specify otherwise in Project»Properties✼/C++✺dvanced. To specify C calling conventions, you do not need to do anything.

Most DLL functions use standard calling conventions, but LabVIEW can call either. Usually, there are two choices: C calling convention or standard calling conventions, also called Pascal and WINAPI.

The last thing that you might need to do before compiling the DLL is to specify the calling convention for the functions that you want to export. See also Microsoft's Exporting from a DLL Using DEF Files In the Linker folder, click the Input property page and modify the Module Definition File property to /DEF. To change this option, select Project» Properties. def file of the same name as the project in the project directory. GetSphereSAandVol you have properly created your DLL project, then the linker automatically looks for a . Calculate the surface area and volume of a sphere with given radius Int GetSphereSAandVol(double radius, double* sa, double* vol) Once the DllMain function is complete, write the routines that you intend to access from the DLL.Perform actions based on the reason for calling. HINSTANCEhinstDLL, // handle to DLL moduleĭWORD fdwReason, // reason for calling function If a library initialization is required, you might need a more complete DllMain:.Unless you must do a specific initialization of the library, the default DllMain that MSVC created is sufficient.Every DLL file must have a DllMain function, which is the entry point for the library.Determine your DllMain function needs and edit the function if necessary.The stdafx.cpp file is necessary, but you do not generally need to edit it. cpp) file, which has the same name as the project. MSVC creates a DLL project with one source (.

How to edit dll files in visual studio