[Python-Dev] Is __declspec(dllexport) really needed on Windows?

[M.-A. Lemburg]

Greg Ewing wrote:
> Someone told me that Pyrex should be generating
> __declspec(dllexport) for the module init func.
> But someone else says this is only needed if
> you're importing a dll as a library, and that
> it's not needed for Python extensions.
> 
> Can anyone who knows what they're doing on
> Windows give me a definitive answer about
> whether it's really needed or not?

You need to export at least the init<modulename>()
API and that is usually done using the dllexport
flag.

Note that this is only needed for shared modules
(DLLs), not modules which are linked statically.

This is what I use for this:

/* Macro to "mark" a symbol for DLL export */

#if (defined(_MSC_VER) && _MSC_VER > 850		\
      || defined(__MINGW32__) || defined(__CYGWIN) || defined(__BEOS__))
# ifdef __cplusplus
#   define MX_EXPORT(type) extern "C" type __declspec(dllexport)
# else
#   define MX_EXPORT(type) extern type __declspec(dllexport)
# endif
#elif defined(__WATCOMC__)
#   define MX_EXPORT(type) extern type __export
#elif defined(__IBMC__)
#   define MX_EXPORT(type) extern type _Export
#else
#   define MX_EXPORT(type) extern type
#endif

-- 
Marc-Andre Lemburg
CEO eGenix.com Software GmbH
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