1/* Create a periodic timer.
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 <support/check.h>
20#include <support/support.h>
21#include <support/xsignal.h>
22#include <time.h>
23
24static void
25dummy_alrm_handler (int sig)
26{
27}
28
29timer_t
30support_create_timer (uint64_t sec, long int nsec, bool repeat,
31 void (*callback)(int))
32{
33 struct sigaction sa;
34 sa.sa_handler = callback != NULL ? callback : dummy_alrm_handler;
35 sigemptyset (set: &sa.sa_mask);
36 sa.sa_flags = 0;
37 xsigaction (SIGALRM, newact: &sa, NULL);
38
39 struct sigevent ev = {
40 .sigev_notify = SIGEV_SIGNAL,
41 .sigev_signo = SIGALRM
42 };
43 timer_t timerid;
44 int r = timer_create (CLOCK_REALTIME, evp: &ev, timerid: &timerid);
45 if (r == -1)
46 FAIL_EXIT1 ("timer_create: %m");
47
48 /* Single timer with 0.1s. */
49 struct itimerspec its =
50 {
51 { .tv_sec = repeat ? sec : 0, .tv_nsec = repeat ? nsec : 0 },
52 { .tv_sec = sec, .tv_nsec = nsec }
53 };
54 r = timer_settime (timerid: timerid, flags: 0, value: &its, NULL);
55 if (r == -1)
56 FAIL_EXIT1 ("timer_settime: %m");
57
58 return timerid;
59}
60
61/* Disable the timer TIMER. */
62void
63support_delete_timer (timer_t timer)
64{
65 int r = timer_delete (timerid: timer);
66 if (r == -1)
67 FAIL_EXIT1 ("timer_delete: %m");
68 xsignal (SIGALRM, SIG_DFL);
69}
70

source code of glibc/support/support_create_timer.c