https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95130
--- Comment #22 from Tomas Kalibera <tomas.kalibera at gmail dot com> --- (In reply to CVS Commits from comment #21) > The master branch has been updated by Jonathan Yong <jy...@gcc.gnu.org>: > > https://gcc.gnu.org/g:966f3c134bb4802ac7ba0517de4e8e3f6384cfa3 > > commit r14-3334-g966f3c134bb4802ac7ba0517de4e8e3f6384cfa3 > Author: Tomas Kalibera <tomas.kalib...@gmail.com> > Date: Sun Aug 20 02:16:16 2023 +0000 > > Fix format attribute for printf > > Since a long time (GCC 4.4?) GCC does support annotating functions > with either the format attribute "gnu_printf" or "ms_printf" to > distinguish between different format string interpretations. > > However, it seems like the attribute is ignored for the "printf" > symbol; regardless what the function declaration says, GCC treats > it as "ms_printf". This has become an issue now that mingw-w64 > supports using the UCRT instead of msvcrt.dll, and in this case > the stdio functions are declared with the gnu_printf attribute, > and inttypes.h uses the same format specifiers as in GNU mode. > > A reproducible example of the problem: > > $ cat format.c > __attribute__((__format__ (gnu_printf, 1, 2))) int printf (const char > *__format, ...); > __attribute__((__format__ (gnu_printf, 1, 2))) int othername (const char > *__format, ...); > > void function(void) { > long long unsigned x = 42; > othername("%llu\n", x); > printf("%llu\n", x); > } > $ x86_64-w64-mingw32-gcc -c -Wformat format.c > format.c: In function 'function': > format.c:7:15: warning: unknown conversion type character 'l' in format > [-Wformat=] > 7 | printf("%llu\n", x); > | ^ > format.c:7:12: warning: too many arguments for format > [-Wformat-extra-args] > 7 | printf("%llu\n", x); > | ^~~~~~~~ > > Note how both functions, printf and othername, are declare with > identical gnu_printf format attributes - GCC does take this into > account for "othername" and doesn't produce a warning, but GCC > seems to disregard the attribute in the printf declaration and > behave as if it was declared as ms_printf. > > If the printf function declaration is changed into a static inline > function, the actual attribute used is honored though. > > gcc/c-family/ChangeLog: > > PR c/95130 > * c-format.cc: skip default format for printf symbol if > explicitly declared by prototype. > > Signed-off-by: Tomas Kalibera <tomas.kalib...@gmail.com> > Signed-off-by: Jonathan Yong <10wa...@gmail.com> Great, thanks a lot for finishing and adding this, Tomas
