1/* Test for difftime
2 Copyright (C) 2021-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <time.h>
20#include <support/check.h>
21
22static void
23test_difftime_helper (time_t t1, time_t t0, double exp_val)
24{
25 double sub = difftime (time1: t1, time0: t0);
26 if (sub != exp_val)
27 FAIL_EXIT1 ("*** Difftime returned %f (expected %f)\n", sub, exp_val);
28}
29
30static int
31do_test (void)
32{
33 time_t t = 1383791700; /* Provide reproductible start value. */
34
35 /* Check if difftime works with current time. */
36 test_difftime_helper (t1: t + 1800, t0: t - 1800, exp_val: 3600.0);
37 test_difftime_helper (t1: t - 1800, t0: t + 1800, exp_val: -3600.0);
38
39 t = 0x7FFFFFFF;
40 /* Check if we run on port with 32 bit time_t size */
41 time_t tov;
42 if (__builtin_add_overflow (t, 1, &tov))
43 return 0;
44
45 /* Check if the time is converted after 32 bit time_t overflow. */
46 test_difftime_helper (t1: t + 1800, t0: t - 1800, exp_val: 3600.0);
47 test_difftime_helper (t1: t - 1800, t0: t + 1800, exp_val: -3600.0);
48
49 t = tov;
50 test_difftime_helper (t1: t + 1800, t0: t - 1800, exp_val: 3600.0);
51 test_difftime_helper (t1: t - 1800, t0: t + 1800, exp_val: -3600.0);
52
53 return 0;
54}
55
56#include <support/test-driver.c>
57

source code of glibc/time/tst-difftime.c