Listing 1: Creating and using a POSIX timer
Listing 1: Creating and using a POSIX timer
#include
#include
void timer_create(int num_secs, int num_nsecs)
{
struct sigaction sa;
struct sigevent sig_spec;
sigset_t allsigs;
struct itimerspec tmr_setting;
timer_t timer_h;
/* setup signal to respond to timer */
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = timer_intr;
if (sigaction(SIGRTMIN, &sa, NULL) < 0)
perror(ýsigactioný);
sig_spec.sigev_notify = SIGEV_SIGNAL;
sig_spec.sigev_signo = SIGRTMIN;
/* create timer, which uses the REALTIME clock */
if (timer_create(CLOCK_REALTIME, &sig_spec, &timer_h) < 0)
perror(ýtimer createý);
/* set the initial expiration and frequency of timer */
tmr_setting.it_value.tv_sec = 1;
tmr_setting.it_value.tv_nsec = 0;
tmr_setting.it_interval.tv_sec = num_secs;
tmr_setting.it_interval.tv_sec = num_nsecs;
if ( timer_settime(timer_h, 0, &tmr_setting,NULL) < 0)
perror(ýsettimerý);
/* wait for signals */
sigemptyset(&allsigs);
while (1) {
sigsuspend(&allsigs);
}
}
/* routine that is called when timer expires */
void timer_intr(int sig, siginfo_t *extra, void *cruft)
{
/* perform periodic processing and then exit */
}
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