Le lun. 5 août 2024 à 11:27, LIU Hao <lh_mo...@126.com> a écrit : > > 在 2024-08-05 01:40, Pali Rohár 写道: > > It looks like that casting whole function pointer to LPVOID type prior > > casting to FARPROC mutes this warning. > > > > Now I remember that in past I have already used casting return value > > from GetProcAddress() to LPVOID and after that to the correct function > > pointer type which muted gcc warnings. > > No, cast to `INT_PTR` instead. Casting between function pointers and object > pointers is undefined > behavior in C; but it's required by POSIX, and is conditionally supported in > C++.
I've casted the return of GetProcAddress in winpthreads through (void *) to avoid the -Wcast-function-type warning too. Note that POSIX 2008 only states that the return of dlsym, which is a (void *), can be converted back to a function pointer, *not* that any function pointer can be converted back and forth to (void *). GCC provides a generic function pointer type: void(*)(void), but neither MSVC nor clang support it. C99 in Annex J.5.7 Function pointer casts states: 1 A pointer to an object or to void may be cast to a pointer to a function, allowing data to be invoked as a function (6.5.4). 2 A pointer to a function may be cast to a pointer to an object or to void, allowing a function to be inspected or modified (for example, by a debugger) (6.5.4) and MSVC, clang, and GCC implement this extension. The C99 standard even defines (u)intptr_t for object pointers only... but all major compilers seem to support casting a function pointer to a (u)intptr_t too. It's a mess! -- Antonin _______________________________________________ Mingw-w64-public mailing list Mingw-w64-public@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
