1 /*	$OpenBSD: test_time_skew.c,v 1.1 2020/07/06 13:33:06 pirofti Exp $ */
2 /*
3  * Copyright (c) 2020 Paul Irofti <paul@irofti.net>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/time.h>
19 
20 #include <assert.h>
21 #include <time.h>
22 #include <stdlib.h>
23 #include <stdio.h>
24 
25 #define ASSERT_EQ(a, b) assert((a) == (b))
26 #define ASSERT_NE(a, b) assert((a) != (b))
27 
28 void
29 check()
30 {
31          struct timespec tp1, tp2, tout;
32 
33          tout.tv_sec = 0;
34          tout.tv_nsec = 100000;
35 
36          ASSERT_EQ(0, clock_gettime(CLOCK_MONOTONIC, &tp1));
37 
38          nanosleep(&tout, NULL);
39 
40          ASSERT_EQ(0, clock_gettime(CLOCK_MONOTONIC, &tp2));
41 
42          /* tp1 should never be larger than tp2 */
43          ASSERT_NE(1, timespeccmp(&tp1, &tp2, >));
44 }
45 
46 int
47 main(void)
48 {
49 	int i;
50 
51 	for (i = 0; i < 1000; i++)
52 		check();
53 
54 	return 0;
55 }
56