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From:   Junio C Hamano <gitster@pobox.com>
To:     Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc:     =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason <avarab@gmail.com>,
        git@vger.kernel.org, Jeff King <peff@peff.net>,
        Denton Liu <liu.denton@gmail.com>,
        Jeff Hostetler <jeffhost@microsoft.com>
Subject: Re: [PATCH] trace2: refactor to avoid gcc warning under -O3
References: <20200404142131.GA679473@coredump.intra.peff.net>
        <patch-1.1-87d9bcf1095-20210505T083951Z-avarab@gmail.com>
        <nycvar.QRO.7.76.6.2105051623230.50@tvgsbejvaqbjf.bet>
        <xmqqv97w1wl1.fsf@gitster.g>
        <nycvar.QRO.7.76.6.2105062229270.50@tvgsbejvaqbjf.bet>
Date:   Fri, 07 May 2021 06:10:53 +0900
In-Reply-To: <nycvar.QRO.7.76.6.2105062229270.50@tvgsbejvaqbjf.bet> (Johannes
        Schindelin's message of "Thu, 6 May 2021 22:29:57 +0200 (CEST)")
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Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

>> Otherwise I'd strongly prefer to see a word that hints that this is
>> an otherwise unneeded workaround for comiplers.  Your suggested
>> title instead hints that it is wrong to assume that errno will be
>> set to non-zero after a syscall.  I do not think that is the message
>> we want to send to our readers.
>
> Right, the oneline I suggested was only for the original patch, with which
> I disagreed.

I actually do not know how your rewrite could be better, though.

		/* GCC thinks socket()/connect() might fail to set errno */
		return errno ? errno : EIO;

If a compiler thinks errno may *not* be set, can 'errno' be reliably
used to decide if it can be returned as-is or a fallback value EIO
should be used, without triggering the same (incorrect) working in
the first place?