about summary refs log tree commit diff
path: root/string/strerror.c
blob: 283ab70f91cd1380538cc739bf33a72cf8e15a53 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
/* Copyright (C) 1991-2020 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <libintl.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

/* Return a string describing the errno code in ERRNUM.
   The storage is good only until the next call to strerror.
   Writing to the storage causes undefined behavior.  */
libc_freeres_ptr (static char *buf);

char *
strerror (int errnum)
{
  char *ret = __strerror_r (errnum, NULL, 0);
  int saved_errno;

  if (__glibc_likely (ret != NULL))
    return ret;
  saved_errno = errno;
  if (buf == NULL)
    buf = malloc (1024);
  __set_errno (saved_errno);
  if (buf == NULL)
    return _("Unknown error");
  return __strerror_r (errnum, buf, 1024);
}