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From: Johannes Sixt <j.sixt@viscovery.net>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings
Date: Thu, 21 Mar 2013 12:45:37 +0100	[thread overview]
Message-ID: <514AF2E1.7020409@viscovery.net> (raw)
In-Reply-To: <20130321110338.GA18552@sigill.intra.peff.net>

Am 3/21/2013 12:03, schrieb Jeff King:
> I was fooling around with clang and noticed that it complains about the
> "int x = x" construct under -Wall. That is IMHO a deficiency in clang,
> since the idiom has a well-defined use in silencing -Wuninitialized
> warnings.

IMO, that's a myth. The construct invokes undefined behavior at least
since C99, and the compilers are right to complain about it.

But you might just say that standards are not worth the paper they are
printed on, and you may possibly be right for practical reasons. But I
still consider it a myth that "int x = x" is an idiom. I'm in the C
business since more than 25 years, and the first time I saw the "idiom"
was in git code. Is there any evidence that the construct is used
elsewhere? Have I been in the wrong corner of the C world for such a long
time?

-- Hannes

  parent reply	other threads:[~2013-03-21 11:46 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-21 11:03 [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Jeff King
2013-03-21 11:05 ` [PATCH 1/4] wt-status: fix possible use of uninitialized variable Jeff King
2013-03-21 19:49   ` Jonathan Nieder
2013-03-21 19:55     ` Junio C Hamano
2013-03-21 19:58       ` Jonathan Nieder
2013-03-22 16:15     ` Jeff King
2013-03-21 11:08 ` [PATCH 2/4] fast-import: use pointer-to-pointer to keep list tail Jeff King
2013-03-21 20:43   ` Jonathan Nieder
2013-03-21 11:10 ` [PATCH 3/4] drop some obsolete "x = x" compiler warning hacks Jeff King
2013-03-21 15:16   ` Erik Faye-Lund
2013-03-21 20:47   ` Jonathan Nieder
2013-03-24  7:17     ` Torsten Bögershausen
2013-03-21 11:13 ` [PATCH 4/4] transport: drop "int cmp = cmp" hack Jeff King
2013-03-21 20:59   ` Jonathan Nieder
2013-03-24  4:00   ` Junio C Hamano
2013-03-24  9:32     ` Jeff King
2013-03-24 14:54       ` Torsten Bögershausen
2013-03-25 19:50       ` Junio C Hamano
2013-03-25 21:06         ` Jeff King
2013-03-25 21:55           ` Junio C Hamano
2013-03-21 11:45 ` Johannes Sixt [this message]
2013-03-21 11:55   ` [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Jeff King
2013-03-21 14:58     ` Junio C Hamano
2013-03-21 15:19       ` Junio C Hamano
2013-03-21 15:44         ` Jeff King
2013-03-21 15:44           ` [PATCH 5/4] fast-import: clarify "inline" logic in file_change_m Jeff King
2013-03-21 15:45           ` [PATCH 6/4] run-command: always set failed_errno in start_command Jeff King
2013-03-21 21:02           ` [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Jonathan Nieder
2013-03-22 16:18           ` Jeff King
2013-03-22 16:19             ` [PATCH 7/4] submodule: clarify logic in show_submodule_summary Jeff King
2013-03-22 21:10               ` Junio C Hamano
2013-03-22 16:21             ` [PATCH 8/4] match-trees: drop "x = x" initializations Jeff King
2013-03-22 21:26               ` Junio C Hamano
2013-03-22 21:33                 ` Junio C Hamano
2013-03-22 21:36                   ` Jeff King
2013-03-23 18:57               ` René Scharfe
2013-03-24  4:55                 ` Junio C Hamano
2013-03-24 10:01                   ` Jeff King
2013-03-24 22:46                   ` René Scharfe
2013-03-25 16:10                     ` Junio C Hamano
2013-03-21 13:44   ` [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Joachim Schmitz
2013-03-21 13:56     ` Joachim Schmitz

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