Re: [RFC] Correctly handling MinGW-w64

["Óscar Fuentes" <ofv@wanadoo.es>]

Paul Eggert <eggert@cs.ucla.edu> writes:

> Óscar Fuentes wrote:
>> +dnl We need to distinguish MinGW32 toolset from its spin-off
>> +dnl MinGW-w64. (This has nothing to do with word size.)
>> +MINGW_W64=no
>> +if test $opsys = mingw32; then
>> +    AC_CHECK_DECL(__MINGW64_VERSION_MAJOR,
>> +                   MINGW_W64=yes,
>> +                   MINGW_W64=no,
>> +                   [#include <_mingw.h>])
>> +    if test "$MINGW_W64" = "yes"; then
>> +       AC_DEFINE([MINGW_W64], 1,
>> +          [Define to 1 if you are using the MinGW-w64 toolset, regardless of word size.])
>> +    fi
>> +fi
>
> Why does the above need to be in configure.ac?  Can the relevant code
> just inspect __MINGW64_VERSION_MAJOR instead of inspecting MINGW_W64?

The key here is that __MINGW64_VERSION_MAJOR is defined on a header
(_mingw.h) so we would need to do

#if __MINGW32__
#include <_mingw.h>
#if __MINGW64_VERSION_MAJOR
...

> Or, if we prefer to use our own symbol, can we just put something like
> this:
>
> #ifdef __MINGW64_VERSION_MAJOR
> # define MINGW_W64 1
> #endif
>
> into ms-w32.h or into some other header specific to Microsoft Windows?

We don't have a header that is included by all the .c files, right?
(apart from configure.h, of course.) The need to test for MINGW_W64 can
occur anywhere.

OTOH, I would be happy to use any practical solution that avoids
configure.ac.