glibc/rt/timer_gettime.c

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/* Copyright (C) 2000-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <pthread.h>
#include <time.h>
#include "posix-timer.h"
/* Get current value of timer TIMERID and store it in VALUE. */
int
timer_gettime (timer_t timerid, struct itimerspec *value)
{
struct timer_node *timer;
struct timespec now, expiry;
int retval = -1, armed = 0, valid;
clock_t clock = 0;
pthread_mutex_lock (&__timer_mutex);
timer = timer_id2ptr (timerid);
valid = timer_valid (timer);
if (valid) {
armed = timer->armed;
expiry = timer->expirytime;
clock = timer->clock;
value->it_interval = timer->value.it_interval;
}
pthread_mutex_unlock (&__timer_mutex);
if (valid)
{
if (armed)
{
__clock_gettime (clock, &now);
if (timespec_compare (&now, &expiry) < 0)
timespec_sub (&value->it_value, &expiry, &now);
else
{
value->it_value.tv_sec = 0;
value->it_value.tv_nsec = 0;
}
}
else
{
value->it_value.tv_sec = 0;
value->it_value.tv_nsec = 0;
}
retval = 0;
}
else
__set_errno (EINVAL);
return retval;
}