support/xsysconf.c

   1 /* Error-checking wrapper for sysconf.
   2    Copyright (C) 2017-2020 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <support/check.h>
  21 #include <support/xunistd.h>
  22
  23 long
  24 xsysconf (int name)
  25 {
  26   /* Detect errors by a changed errno value, in case -1 is a valid
  27      value.  Make sure that the caller does not see the zero value for
  28      errno.  */
  29   int old_errno = errno;
  30   errno = 0;
  31   long result = sysconf (name);
  32   if (errno != 0)
  33     FAIL_EXIT1 ("sysconf (%d): %m", name);
  34   errno = old_errno;
  35   return result;
  36 }