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glibc  2.9
strerror.c
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00001 /* Copyright (C) 1991, 93, 94, 95, 96, 98, 2002 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <libintl.h>
00020 #include <stdio.h>
00021 #include <string.h>
00022 #include <errno.h>
00023 
00024 /* Return a string describing the errno code in ERRNUM.
00025    The storage is good only until the next call to strerror.
00026    Writing to the storage causes undefined behavior.  */
00027 libc_freeres_ptr (static char *buf);
00028 
00029 char *
00030 strerror (errnum)
00031      int errnum;
00032 {
00033   char *ret = __strerror_r (errnum, NULL, 0);
00034   int saved_errno;
00035 
00036   if (__builtin_expect (ret != NULL, 1))
00037     return ret;
00038   saved_errno = errno;
00039   if (buf == NULL)
00040     buf = malloc (1024);
00041   __set_errno (saved_errno);
00042   if (buf == NULL)
00043     return _("Unknown error");
00044   return __strerror_r (errnum, buf, 1024);
00045 }