posix/tst-nice.c

   1 /* Copyright (C) 2003 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 <errno.h>
  20 #include <stdio.h>
  21 #include <unistd.h>
  22
  23
  24 /* Test that nice() does not incorrectly return 0.  */
  25 static int
  26 do_test (void)
  27 {
  28   int ret;
  29   const int incr = 10;
  30   int old;
  31
  32   /* Discover current nice value.  */
  33   errno = 0;
  34   old = nice (0);
  35   if (old == -1 && errno != 0)
  36     {
  37       printf ("break: nice(%d) return: %d, %m\n", 0, old);
  38       return 1;
  39     }
  40
  41   /* Nice ourselves up.  */
  42   errno = 0;
  43   ret = nice (incr);
  44   if (ret == -1 && errno != 0)
  45     {
  46       printf ("break: nice(%d) return: %d, %m\n", incr, ret);
  47       return 1;
  48     }
  49
  50   /* Check for return value being zero when it shouldn't.  Cannot simply
  51      check for expected value since nice values are capped at 2^n-1.
  52      But we assume that we didn't start at the cap and so should have
  53      increased some.  */
  54   if (ret <= old)
  55     {
  56       printf ("FAIL: retval (%d) of nice(%d) != %d\n", ret, incr, old + incr);
  57       return 1;
  58     }
  59
  60   printf ("PASS: nice(%d) from %d return: %d\n", incr, old, ret);
  61
  62   return 0;
  63 }
  64
  65 #define TEST_FUNCTION do_test ()
  66 #include "../test-skeleton.c"