gl/strerror.c

   1 /* strerror.c --- ANSI C compatible system error routine
   2
   3    Copyright (C) 1986, 1988, 1989, 1991, 2002, 2003 Free Software
   4    Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include <limits.h>
  25
  26 /* Don't include <stdio.h>, since it may or may not declare
  27    sys_errlist and its declarations may collide with ours.  Just
  28    declare the stuff that we need directly.  Standard hosted C89
  29    implementations define strerror and they don't need this strerror
  30    function, so take some liberties with the standard to cater to
  31    ancient or limited freestanding implementations.  */
  32 int sprintf (char *, char const *, ...);
  33 extern int sys_nerr;
  34 extern char *sys_errlist[];
  35
  36 char *
  37 strerror (int n)
  38 {
  39   static char const fmt[] = "Unknown error (%d)";
  40   static char mesg[sizeof fmt + sizeof n * CHAR_BIT / 3];
  41
  42   if (n < 0 || n >= sys_nerr)
  43     {
  44       sprintf (mesg, fmt, n);
  45       return mesg;
  46     }
  47   else
  48     return sys_errlist[n];
  49 }