When Building a DLL with LabVIEW is "standard" or "c" calling convention more common?

[Gregory]

I'm building a DLL with LabVIEW so that others can hopefully call it with their programming language of choice. When I define the prototype for the function I'm given the option of using "standard calling conventions" or "c calling conventions". Is one of these choices preferred?

[rolfk · Accepted solution]

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@Gregory wrote:

I'm building a DLL with LabVIEW so that others can hopefully call it with their programming language of choice. When I define the prototype for the function I'm given the option of using "standard calling conventions" or "c calling conventions". Is one of these choices preferred?

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First, this is only an option for 32-bit DLLs. 64-bit DLLs always should use fastcall calling convention for normal C function calls in user space. This is the default calling convention for 64-bit Windows C compilers.

For 32-bit DLLs, cdecl is the default calling convention for even Microsoft Visual Studio compilers, even though the entire Windows API uses almost exclusively stdcall.

Personally I only use stdcall if it is required for some reason. Technically the only reason would be if you need to pass a function pointer to an existing API that is using stdcall. There is really no other reason to choose for stdcall. Every 32-bit environment that allows calling DLLs in some way supports both cdecl and stdcall.

[Gregory]

Thank you Rolf!