From: "Richard Guenther" <richard.guenther@gmail.com>
To: "Joe Buck" <Joe.Buck@synopsys.com>
Cc: "Ismail Dönmez" <ismail@pardus.org.tr>, gcc@gcc.gnu.org
Subject: Re: Changes in C++ FE regarding pedwarns to be errors are harmful
Date: Tue, 08 Jan 2008 21:43:00 -0000 [thread overview]
Message-ID: <84fc9c000801081343y2f0dc0f6me42ecdf10fff19e6@mail.gmail.com> (raw)
In-Reply-To: <20080108213413.GF23110@synopsys.com>
On Jan 8, 2008 10:34 PM, Joe Buck <Joe.Buck@synopsys.com> wrote:
> On Tue, Jan 08, 2008 at 11:28:22PM +0200, Ismail Dönmez wrote:
> > Hi all,
> >
> > Looks like gcc 4.3 has some rather inconvenient changes in C++ FE, with the
> > latest trunk. Lets see with an example :
> >
> > [~]> cat test.cpp
> > #define foo bar
> > #define foo baz
> >
> > [~]> g++ -c test.cpp
> > test.cpp:2:1: error: "foo" redefined
> > test.cpp:1:1: error: this is the location of the previous definition
> >
> > I don't know the reasoning behind this change but this breaks many C++
> > programs unless -fpermissive is used. Why? Because everybody loves to install
> > their own config.h (Python, libmp4v2 being nice examples) which just
> > carelessly #define anything its asked for with ifndef ... endif .
> >
> > Now flash back to real world: this breaks any C++ application that uses
> > Python, libmp4v2, libjpeg and possibly many others. And I think this is a
> > real bad behaviour change and I am not sure if its worth all the trouble.
>
> There's certainly an argument that this change is ill-advised. However,
> your statements in the last paragraph aren't true: most quality open
> source projects have a "no warnings" rule (or at least try to eliminate
> warnings), and most programmers know about #undef. Since people have
> already built whole distros with the gcc from the trunk, clearly they
> are managing to build C++ applications that use Python, libmp4v2, libjpeg
> etc.
Yep, in the worst case we stick a -fpermissive in. See also PR33907 for
more obscure cases of the standard.
Richard.
next prev parent reply other threads:[~2008-01-08 21:43 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-08 21:27 Ismail Dönmez
2008-01-08 21:34 ` Joe Buck
2008-01-08 21:43 ` Richard Guenther [this message]
2008-01-08 21:44 ` Ismail Dönmez
2008-01-08 22:13 ` Andrew Pinski
2008-01-08 22:29 ` Manuel López-Ibáñez
2008-01-08 22:36 ` Ismail Dönmez
2008-01-08 22:45 ` Andrew Pinski
2008-01-09 14:10 ` Paolo Bonzini
2008-01-09 15:38 ` Manuel López-Ibáñez
2008-01-09 15:57 ` Paolo Bonzini
2008-01-08 22:51 ` Manuel López-Ibáñez
2008-01-08 23:02 ` Ismail Dönmez
2008-01-09 1:23 ` Ismail Dönmez
2008-01-09 2:25 ` Manuel López-Ibáñez
2008-01-09 16:47 ` Ian Lance Taylor
2008-01-09 18:11 ` Benjamin Kosnik
2008-01-09 18:18 ` Andrew Pinski
2008-01-09 18:21 ` Paolo Carlini
2008-01-09 19:42 ` Mark Mitchell
2008-01-11 17:06 ` Jason Merrill
2008-01-11 17:12 ` Joe Buck
2008-01-11 17:55 ` Mark Mitchell
2008-01-12 19:07 ` Jonathan Wakely
2008-01-12 19:50 ` Manuel López-Ibáñez
2008-01-13 3:28 ` Jonathan Wakely
2008-01-13 15:30 ` Manuel López-Ibáñez
2008-01-13 22:56 ` Jonathan Wakely
2008-01-14 2:04 ` Jonathan Wakely
2008-01-14 2:19 ` Manuel López-Ibáñez
2008-01-13 15:33 ` Gabriel Dos Reis
2008-01-13 15:36 ` Ismail Dönmez
2008-01-13 16:09 ` Andreas Schwab
2008-01-13 16:10 ` Ismail Dönmez
2008-01-13 16:13 ` Richard Guenther
2008-01-13 16:41 ` Ismail Dönmez
2008-01-13 23:08 ` Manuel López-Ibáñez
2008-01-14 11:03 ` Paolo Bonzini
2008-01-14 16:23 ` Ismail Dönmez
2008-01-13 16:43 ` Gabriel Dos Reis
2008-01-13 16:45 ` Ismail Dönmez
2008-01-13 19:17 ` Gabriel Dos Reis
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