1/* Copyright (C) 2000-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public License as
6 published by the Free Software Foundation; either version 2.1 of the
7 License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If
16 not, see <https://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <pthread.h>
20#include <time.h>
21
22#include "posix-timer.h"
23
24
25/* Get current value of timer TIMERID and store it in VLAUE. */
26int
27timer_gettime (timer_t timerid, struct itimerspec *value)
28{
29 struct timer_node *timer;
30 struct timespec now, expiry;
31 int retval = -1, armed = 0, valid;
32 clock_t clock = 0;
33
34 pthread_mutex_lock (mutex: &__timer_mutex);
35
36 timer = timer_id2ptr (timerid);
37 valid = timer_valid (timer);
38
39 if (valid) {
40 armed = timer->armed;
41 expiry = timer->expirytime;
42 clock = timer->clock;
43 value->it_interval = timer->value.it_interval;
44 }
45
46 pthread_mutex_unlock (mutex: &__timer_mutex);
47
48 if (valid)
49 {
50 if (armed)
51 {
52 __clock_gettime (clock, &now);
53 if (timespec_compare (left: &now, right: &expiry) < 0)
54 timespec_sub (diff: &value->it_value, left: &expiry, right: &now);
55 else
56 {
57 value->it_value.tv_sec = 0;
58 value->it_value.tv_nsec = 0;
59 }
60 }
61 else
62 {
63 value->it_value.tv_sec = 0;
64 value->it_value.tv_nsec = 0;
65 }
66
67 retval = 0;
68 }
69 else
70 __set_errno (EINVAL);
71
72 return retval;
73}
74

source code of glibc/rt/timer_gettime.c