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Subject: [Bug c++/87656] Useful flags to enable with -Wall or -Wextra
Date: Thu, 28 Apr 2022 16:56:24 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D87656

--- Comment #12 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to David Binderman from comment #11)
> -Wold-style-definition
>=20
> KnR style function definitions have been deprecated for about 35 years.

+1

> Yes, there is a warning for it in gcc, but that warning isn't in either
> -Wall or -Wextra.=20
>=20
> Also, switching on -std=3Dc2x only makes it a warning, not an error.=20
> That doesn't sound correct to me. AFAIK KnR is removed from c2x.

It can stay there as a GCC extension no problem.  If there is a warning for=
 it
it is not a problem anymore, esp. if that warning is in -Wall or on by defa=
ult
even.

The only reason to remove support for this is if it actually simplifies the
compiler code itself, which means we have to completely not support it anym=
ore.
So let's first have a default warning, and then see if anything in the wild
still uses old-style functions defs?=