Hi all, I'd like to call attention to an issue I've been looking into for the past couple days:
https://github.com/cython/cython/pull/360 To summarize the discussion, when building DLLs for Windows, functions that should be exported by that DLL must be marked __declspec(dllexport) in their declaration. However, when using the same header file in a project that links to that DLL the same function must be declared __declspec(dllimport). It's common practice to have a macro for this, whose value is controlled by whether or not a macro (often called something like "DLL_EXPORT"). When compiling the DLL we would define -DDLL_EXPORT to output __declspec(dllexport). Otherwise it outputs __declspec(dllimport). Cython currently handles this with such a macro called DL_IMPORT which comes from Python. However, this macro was deprecated some time ago, and is removed in current Python 3 versions. So Cython must replace it with its own. I'm working on a patch for this--to reduce confusion the macro is named specifically for the Cython module it's associated with. For example, for a Cython module named "foo.bar" there are two macros DLL_EXPORT__foo__bar and EXPORT__foo__bar. If the latter is defined then the former outputs dllexport, otherwise it outputs dllimport. I've attached the patch in progress. I'm open to comment on this, but where I'm stuck now is that in order for the "foo.bar" module to be compiled correctly it needs EXPORT__foo__bar to be defined at compile time. And it's not clear to me what the best way is for the Cython compiler to pass down options that are passed to the C/C++ compiler. In general the best way would be to attach this to the define_macros attribute of the associated distutils/setuptools Extension object and let the distutils compiler class generate the right compiler options. But it's not clear to me from Cython's internals where the best place to do that would be. Thanks, Erik
dll_export.patch
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