GNU bug report logs - #9612
sort: avoid a NaN-induced infloop

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Message #11 received at 9612 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Andreas Schwab <schwab <at> linux-m68k.org>
Cc: 9612 <at> debbugs.gnu.org
Subject: Re: bug#9612: sort: avoid a NaN-induced infloop
Date: Tue, 27 Sep 2011 19:24:25 +0200

Andreas Schwab wrote:
> Jim Meyering <jim <at> meyering.net> writes:
>
>> The statement "long double x = NAN;" (inside glibc's strtold) leaves many
>> bits of "x" uninitialized.
>
> You are looking at padding bits, which have unspecified contents.

I realize that they are unspecified.
That is why I did not claim that this is a POSIX violation.
POSIX says little about what strtold must do for a "NaN" string.
However, I am dismayed that with glibc's strtold the values of those bits
is not deterministic.  That makes sorting NaN values obtained from strtold
unnecessarily hard.

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