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glibc  2.9
tst-nice.c
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00001 /* Copyright (C) 2003 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <stdio.h>
00021 #include <unistd.h>
00022 
00023 
00024 /* Test that nice() does not incorrectly return 0.  */
00025 static int
00026 do_test (void)
00027 {
00028   int ret;
00029   const int incr = 10;
00030   int old;
00031 
00032   /* Discover current nice value.  */
00033   errno = 0;
00034   old = nice (0);
00035   if (old == -1 && errno != 0)
00036     {
00037       printf ("break: nice(%d) return: %d, %m\n", 0, old);
00038       return 1;
00039     }
00040 
00041   /* Nice ourselves up.  */
00042   errno = 0;
00043   ret = nice (incr);
00044   if (ret == -1 && errno != 0)
00045     {
00046       printf ("break: nice(%d) return: %d, %m\n", incr, ret);
00047       return 1;
00048     }
00049 
00050   /* Check for return value being zero when it shouldn't.  Cannot simply
00051      check for expected value since nice values are capped at 2^n-1.
00052      But we assume that we didn't start at the cap and so should have
00053      increased some.  */
00054   if (ret <= old)
00055     {
00056       printf ("FAIL: retval (%d) of nice(%d) != %d\n", ret, incr, old + incr);
00057       return 1;
00058     }
00059 
00060   printf ("PASS: nice(%d) from %d return: %d\n", incr, old, ret);
00061 
00062   return 0;
00063 }
00064 
00065 #define TEST_FUNCTION do_test ()
00066 #include "../test-skeleton.c"