glibc/posix/tst-nice.c

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/* Copyright (C) 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
/* Test that nice() does not incorrectly return 0. */
static int
do_test (void)
{
int ret;
const int incr = 10;
int old;
/* Discover current nice value. */
errno = 0;
old = nice (0);
if (old == -1 && errno != 0)
{
printf ("break: nice(%d) return: %d, %m\n", 0, old);
return 1;
}
/* Nice ourselves up. */
errno = 0;
ret = nice (incr);
if (ret == -1 && errno != 0)
{
printf ("break: nice(%d) return: %d, %m\n", incr, ret);
return 1;
}
/* Check for return value being zero when it shouldn't. Cannot simply
check for expected value since nice values are capped at 2^n-1.
But we assume that we didn't start at the cap and so should have
increased some. */
if (ret <= old)
{
printf ("FAIL: retval (%d) of nice(%d) != %d\n", ret, incr, old + incr);
return 1;
}
printf ("PASS: nice(%d) from %d return: %d\n", incr, old, ret);
return 0;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"