GNU bug report logs - #2790
emacs 22.1.1 cannot open 5GB file on 64GB 64-bit Linux box

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Package: emacs;

Reported by: Mike Coleman <tutufan <at> gmail.com>

Date: Thu, 26 Mar 2009 16:00:03 UTC

Severity: normal

Done: Eli Zaretskii <eliz <at> gnu.org>

Bug is archived. No further changes may be made.

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Message #175 received at 2790 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Andreas Schwab <schwab <at> linux-m68k.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 2790 <at> debbugs.gnu.org, Eli Zaretskii <eliz <at> gnu.org>,
        tutufan <at> gmail.com
Subject: Re: bug#2790: emacs 22.1.1 cannot open 5GB file on 64GB 64-bit	GNU/Linux box
Date: Mon, 30 Mar 2009 10:08:10 +0200

Stefan Monnier <monnier <at> iro.umontreal.ca> writes:

> I do not know what you're referring to.  If you're referring to the fact
> that (((EMACS_INT)st.st_size)*4) may overflow, then I'm not sure what
> problem you're envisaging:

The compiler can (and does) optimize on the fact that overflow does not
occur, thus the operation x*4/4 becomes a no-op.  Never ever do overflow
checking after the fact.

Andreas.

-- 
Andreas Schwab, schwab <at> linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."
This bug report was last modified 13 years and 316 days ago.

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