1 /*
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright © 2020 Keith Packard
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following
15 * disclaimer in the documentation and/or other materials provided
16 * with the distribution.
17 *
18 * 3. Neither the name of the copyright holder nor the names of its
19 * contributors may be used to endorse or promote products derived
20 * from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
27 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
33 * OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36 #include <sys/times.h>
37 #include <sys/time.h>
38 #include <stdlib.h>
39 #include <math.h>
40 #include <stdio.h>
41 #include <unistd.h>
42
43 int
main(void)44 main(void)
45 {
46 struct tms begin_tms, end_tms;
47 clock_t begin, end;
48 double y;
49 double x;
50 double seconds;
51 long ticks_per_second;
52
53 begin = end = times(&begin_tms);
54 y = 0.0;
55 for (x = -100; x < 100; x += 0.001) {
56 y += sin(x)*sin(x) + cos(x)*cos(x);
57 end = times(&end_tms);
58 if (end != begin)
59 break;
60 }
61 printf("%.17g\n", y);
62 ticks_per_second = sysconf(_SC_CLK_TCK);
63 seconds = ((double) (end - begin)) / (double) ticks_per_second;
64 printf("delta %ld seconds %.17g\n", (long) end - (long) begin, seconds);
65 exit(end == begin);
66 }
67
