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From: =?ISO-8859-1?Q?Manuel_L=F3pez=2DIb=E1=F1ez?= <lopezibanez@gmail.com>
Date: Tue, 23 Oct 2012 19:38:00 -0000
Message-ID: <CAESRpQByQJBAWhMtX3iJQUAePdq6Ov7nhThMAgM4MR2yyeV1Wg@mail.gmail.com>
Subject: Re: PR c/53063 Handle Wformat with LangEnabledBy
To: "Joseph S. Myers" <joseph@codesourcery.com>
Cc: Gcc Patch List <gcc-patches@gcc.gnu.org>
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On 19 October 2012 18:17, Joseph S. Myers <joseph@codesourcery.com> wrote:
> On Wed, 17 Oct 2012, Manuel L=F3pez-Ib=E1=F1ez wrote:
>
>> documentation but I can also implement -Wformat=3D0 being an alias for
>> -Wno-format and -Wformat=3D1 an alias for -Wformat and simply reject
>> -Wno-format=3D.
>
> I think that's what's wanted; -Wno-format=3D should be rejected, -Wformat=
=3D
> should take an arbitrary integer level (of which at present all those
> above 2 are equivalent to 2, just as -O<n> for n > 3 is equivalent to
> -O3).

The problem is how to represent that Wformat-y2k is enabled by
-Wformat=3DX with X >=3D 2, while Wformat-zero-length is enabled by X >=3D1.

One possiblity is to allow to specify a condition directly:

Wformat-y2k
C ObjC C++ ObjC++ Var(warn_format_y2k) Warning LangEnabledByCond(C
ObjC C++ ObjC++,Wformat=3D,warn_format >=3D 2)
Warn about strftime formats yielding 2-digit years

Wformat-zero-length
C ObjC C++ ObjC++ Var(warn_format_zero_length) Warning
LangEnabledByCond(C ObjC C++ ObjC++,Wformat=3D,warn_format >=3D 2)
Warn about zero-length formats

Wformat=3D
C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_format) Warning

I think this is both flexible and easy to implement given the current
infrastructure. But I wanted to get your approval before. What do you
think?