src/posix/error.c

   1 /*****************************************************************************
   2  * error.c: POSIX error messages formatting
   3  *****************************************************************************
   4  * Copyright © 2013 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) 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 Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser 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
  21 #ifdef HAVE_CONFIG_H
  22 # include "config.h"
  23 #endif
  24
  25 #include <string.h>
  26 #include <errno.h>
  27 #include <locale.h>
  28 #include <assert.h>
  29
  30 #include <vlc_common.h>
  31
  32 static const char *vlc_strerror_l(int errnum, const char *lname)
  33 {
  34     int saved_errno = errno;
  35     locale_t loc = newlocale(LC_MESSAGES_MASK, lname, (locale_t)0);
  36
  37     if (unlikely(loc == (locale_t)0))
  38     {
  39         if (errno == ENOENT) /* fallback to POSIX locale */
  40             loc = newlocale(LC_MESSAGES_MASK, "C", (locale_t)0);
  41
  42         if (unlikely(loc == (locale_t)0))
  43         {
  44             assert(errno != EINVAL && errno != ENOENT);
  45             errno = saved_errno;
  46             return "Error message unavailable";
  47         }
  48         errno = saved_errno;
  49     }
  50
  51     const char *buf = strerror_l(errnum, loc);
  52
  53     freelocale(loc);
  54     return buf;
  55 }
  56
  57 /**
  58  * Formats an error message in the current locale.
  59  * @param errnum error number (as in errno.h)
  60  * @return A string pointer, valid until the next call to a function of the
  61  * strerror() family in the same thread. This function cannot fail.
  62  */
  63 const char *vlc_strerror(int errnum)
  64 {
  65     /* We cannot simply use strerror() here, since it is not thread-safe. */
  66     return vlc_strerror_l(errnum, "");
  67 }
  68
  69 /**
  70  * Formats an error message in the POSIX/C locale (i.e. American English).
  71  * @param errnum error number (as in errno.h)
  72  * @return A string pointer, valid until the next call to a function of the
  73  * strerror() family in the same thread. This function cannot fail.
  74  */
  75 const char *vlc_strerror_c(int errnum)
  76 {
  77     return vlc_strerror_l(errnum, "C");
  78 }