On Wed, 18 Sep 2024, Jacek Caban wrote:
On 18.09.2024 14:06, Martin Storsjö wrote:
Modern GCC and Clang warn for these casts, with warnings like these:
../secapi/_chsize_s.c:20:6:
warning: cast from 'FARPROC' (aka 'long long (*)()') to 'errno_t
((*))(int, long long) __attribute__((cdecl))' (aka 'int (*)(int, lo
ng long)') converts to incompatible function type
[-Wcast-function-type-mismatch]
20 | f = (errno_t __cdecl (*)(int, long long))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
21 | GetProcAddress (__mingw_get_msvcrt_handle (),
"_chsize_s");
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
That warning seems very impractical in code dealing with GetProcAddress. In
Wine, we usually just cast it to (void *), but I recall that it was
problematic for mingw-w64-crt for some reason too. Maybe we could just
disable that warning in the configure script?
It's not strictly problematic to use regular (void*) casts, they also work
the same. But some people raised that, in a strict language context, it
isn't safe to cast function pointers to object pointers - even if it is ok
in all practical contexts we operate in.
Disabling the warning could work, but that's a bit of build system work -
checking for whether the warning option is supported has a few surprising
pitfalls, as some compilers silently accept unknown warning options and
then popping up warnings later, see
https://github.com/llvm/llvm-project/commit/e546bbfda0ab91cf78c096d8c035851cc7c3b9f3.
So if possible to write code that in itself is mostly warnings free with
modern compilers, I kinda prefer that.
// Martin
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