Issue 11722: mingw64 does not link when building extensions (original) (raw)

Bulding a simple extension (the spam example) fails with mingw64.

in modsupport.h, the following is used to detect 64bit, it does not work with mingw64.

#if SIZEOF_SIZE_T != SIZEOF_INT /* On a 64-bit system, rename the Py_InitModule4 so that 2.4 modules cannot get loaded into a 2.5 interpreter */ #define Py_InitModule4 Py_InitModule4_64 #endif

This code never compiles, you can test this by placing similar code and filling it with rubbish.

This means it thinks the extension is being built on a 32bit compiler and creates the wrong call for Py_InitModule.

Workaround: Explicitly calling Py_InitModule4_64() in extension and declaring Py_InitModule4_64(...) in code. Note this does not complain about re-declaration and builds OK because declaration is wrong. e.g. //m=Py_InitModule("spam", SpamMethods); m = Py_InitModule4_64("spam", SpamMethods,(char *)NULL, (PyObject *)NULL, PYTHON_API_VERSION);

Or, a better more portable permanent fix, define WIN64 in code and modify modsupport.h: #if SIZEOF_SIZE_T != SIZEOF_INT || defined(WIN64) /* On a 64-bit system, rename the Py_InitModule4 so that 2.4 modules cannot get loaded into a 2.5 interpreter */ #define Py_InitModule4 Py_InitModule4_64 #endif

I am sure there are other, more standard ways.

OK, I've understood this a bit more.

The compiler does not cause pyconfig.h to define SIZEOF_SIZE_T and SIZEOF_INT, rather it is the definition of MS_WIN64 at compile time (which was not being defined)

Defining MS_WIN64 fixes the problem, and causes another unrelated one....

I would guess that I would have to change the patch in Issue11723 to define MS_WIN64, how do I then use the same compiler for 32BIT? What is the correct way to pass such flags to the compiler class?