/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright © 2020 Keith Packard
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/times.h>
#include <sys/time.h>
#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#include <unistd.h>

int
main(void)
{
    struct tms begin_tms, end_tms;
    clock_t    begin, end;
    double     y;
    double     x;
    double     seconds;
    long       ticks_per_second;

    begin = end = times(&begin_tms);
    y = 0.0;
    for (x = -100; x < 100; x += 0.001) {
        y += sin(x) * sin(x) + cos(x) * cos(x);
        end = times(&end_tms);
        if (end != begin)
            break;
    }
    printf("%.17g\n", y);
    ticks_per_second = sysconf(_SC_CLK_TCK);
    seconds = ((double)(end - begin)) / (double)ticks_per_second;
    printf("delta %ld seconds %.17g\n", (long)end - (long)begin, seconds);
    exit(end == begin);
}
