lib/strerror.c

   1 /* strerror.c --- ANSI C compatible system error routine
   2
   3    Copyright (C) 1986, 1988, 1989, 1991, 2002, 2003, 2006, 2007 Free
   4    Software 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  19
  20 #include <config.h>
  21
  22 #if REPLACE_STRERROR
  23
  24 # include <string.h>
  25 # include <stdio.h>
  26
  27 # undef strerror
  28
  29 char *rpl_strerror (int n)
  30 {
  31   static char const fmt[] = "Unknown error (%d)";
  32   static char mesg[sizeof fmt + sizeof n * CHAR_BIT / 3];
  33
  34   char *result = strerror (n);
  35
  36   if (! result)
  37     {
  38       sprintf (mesg, fmt, n);
  39       return mesg;
  40     }
  41   return result;
  42 }
  43
  44 #elif !HAVE_STRERROR
  45
  46 #include <limits.h>
  47
  48 /* Don't include <stdio.h>, since it may or may not declare
  49    sys_errlist and its declarations may collide with ours.  Just
  50    declare the stuff that we need directly.  Standard hosted C89
  51    implementations define strerror and they don't need this strerror
  52    function, so take some liberties with the standard to cater to
  53    ancient or limited freestanding implementations.  */
  54 int sprintf (char *, char const *, ...);
  55 extern int sys_nerr;
  56 extern char *sys_errlist[];
  57
  58 char *
  59 strerror (int n)
  60 {
  61   static char const fmt[] = "Unknown error (%d)";
  62   static char mesg[sizeof fmt + sizeof n * CHAR_BIT / 3];
  63
  64   if (n < 0 || n >= sys_nerr)
  65     {
  66       sprintf (mesg, fmt, n);
  67       return mesg;
  68     }
  69   else
  70     return sys_errlist[n];
  71 }
  72
  73 #else
  74
  75 /* This declaration is solely to ensure that after preprocessing
  76    this file is never empty.  */
  77 typedef int dummy;
  78
  79 #endif