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[glibc/history.git] / string / strerror.c
blob5d829d0bf0e2da57b5122fa244ded979ad8927ed
1 /* Copyright (C) 1991, 93, 94, 95, 96, 98, 2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
19 #include <libintl.h>
20 #include <stdio.h>
21 #include <string.h>
22 #include <errno.h>
24 /* Return a string describing the errno code in ERRNUM.
25 The storage is good only until the next call to strerror.
26 Writing to the storage causes undefined behavior. */
27 libc_freeres_ptr (static char *buf);
29 char *
30 strerror (errnum)
31 int errnum;
33 char *ret = __strerror_r (errnum, NULL, 0);
34 int saved_errno;
36 if (__builtin_expect (ret != NULL, 1))
37 return ret;
38 saved_errno = errno;
39 if (buf == NULL)
40 buf = malloc (1024);
41 __set_errno (saved_errno);
42 if (buf == NULL)
43 return _("Unknown error");
44 return __strerror_r (errnum, buf, 1024);