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From: "tomas.kalibera at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c/95130] GCC ignoring attribute(format(gnu_printf)) on printf
 in mingw
Date: Wed, 15 Dec 2021 17:45:30 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95130

--- Comment #5 from Tomas Kalibera <tomas.kalibera at gmail dot com> ---
(In reply to joseph@codesourcery.com from comment #1)
> See bug 92292.  The extra attribute isn't ignored, it simply means the=20
> function has multiple format attributes, which is valid, but should=20
> probably be special-cased for this case of built-in functions.

I've added a draft of a patch to address the issue in the suggested way. I'=
ve
tested it in gcc 10.3.0 on the example from comment 2 (also attached). With=
 the
patch applied, only line (2) gets a warning, as it should.

When deciding whether to emit a format warning for a function with multiple
format attributes, it skips the first format in case it is a builtin known =
to
have a format added by gcc. Please let me know if you have any advice how to
improve (thanks to Martin Liska for helping me with identifying the builtin=
s),
or indeed feel free to adjust and add your way. Fixing this would help the R
community or anyone else who uses GCC with UCRT.

Thanks,
Tomas=