string/_strerror.c

   1 /* Copyright (C) 1991,93,95,96,97,98,2000,2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   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.
   8
   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.
  13
  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.  */
  18
  19 #include <libintl.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <sys/param.h>
  23 #include <stdio-common/_itoa.h>
  24
  25 /* It is critical here that we always use the `dcgettext' function for
  26    the message translation.  Since <libintl.h> only defines the macro
  27    `dgettext' to use `dcgettext' for optimizing programs this is not
  28    always guaranteed.  */
  29 #ifndef dgettext
  30 # include <locale.h>            /* We need LC_MESSAGES.  */
  31 # define dgettext(domainname, msgid) dcgettext (domainname, msgid, LC_MESSAGES)
  32 #endif
  33
  34 /* Return a string describing the errno code in ERRNUM.  */
  35 char *
  36 __strerror_r (int errnum, char *buf, size_t buflen)
  37 {
  38   if (errnum < 0 || errnum >= _sys_nerr_internal
  39       || _sys_errlist_internal[errnum] == NULL)
  40     {
  41       /* Buffer we use to print the number in.  For a maximum size for
  42          `int' of 8 bytes we never need more than 20 digits.  */
  43       char numbuf[21];
  44       const char *unk = _("Unknown error ");
  45       const size_t unklen = strlen (unk);
  46       char *p, *q;
  47
  48       numbuf[20] = '\0';
  49       p = _itoa_word (errnum, &numbuf[20], 10, 0);
  50
  51       /* Now construct the result while taking care for the destination
  52          buffer size.  */
  53       q = __mempcpy (buf, unk, MIN (unklen, buflen));
  54       if (unklen < buflen)
  55         memcpy (q, p, MIN ((size_t) (&numbuf[21] - p), buflen - unklen));
  56
  57       /* Terminate the string in any case.  */
  58       if (buflen > 0)
  59         buf[buflen - 1] = '\0';
  60
  61       return buf;
  62     }
  63
  64   return (char *) _(_sys_errlist_internal[errnum]);
  65 }
  66 weak_alias (__strerror_r, strerror_r)
  67 libc_hidden_def (__strerror_r)