Mercurial > gnulib
view doc/ctime.texi @ 17249:e542fd46ad6f
maint: update all copyright year number ranges
Run "make update-copyright". Compare to commit 1602f0a from last year.
Signed-off-by: Eric Blake <eblake@redhat.com>
author | Eric Blake <eblake@redhat.com> |
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date | Tue, 01 Jan 2013 00:50:58 +0000 |
parents | 8250f2777afc |
children | 344018b6e5d7 |
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@node ctime @section ctime @findex ctime @c Copyright (C) 2005, 2009-2013 Free Software Foundation, Inc. @c Permission is granted to copy, distribute and/or modify this document @c under the terms of the GNU Free Documentation License, Version 1.3 or @c any later version published by the Free Software Foundation; with no @c Invariant Sections, with no Front-Cover Texts, and with no Back-Cover @c Texts. A copy of the license is included in the ``GNU Free @c Documentation License'' file as part of this distribution. The @code{ctime} function need not be reentrant, and consequently is not required to be thread safe. Implementations of @code{ctime} typically write the time stamp into static buffer. If two threads call @code{ctime} at roughly the same time, you might end up with the wrong date in one of the threads, or some undefined string. There is a re-entrant interface @code{ctime_r}, that take a pre-allocated buffer and length of the buffer, and return @code{NULL} on errors. The input buffer should be at least 26 bytes in size. The output string is locale-independent. However, years can have more than 4 digits if @code{time_t} is sufficiently wide, so the length of the required output buffer is not easy to determine. Increasing the buffer size when @code{ctime_r} return @code{NULL} is not necessarily sufficient. The @code{NULL} return value could mean some other error condition, which will not go away by increasing the buffer size. A more flexible function is @code{strftime}. However, note that it is locale dependent.