C : How to pause sigaction Timer - c

Question

There is one function called test(), I want to call this function in every 30 seconds, Please find my implemented code snippet.
void init_sigaction(void) {
struct sigaction act;
act.sa_handler = test; //test()
act.sa_flags = 0;
sigemptyset(&act.sa_mask);
sigaction(SIGPROF, &act, NULL);
}
void init_time(void) {
struct itimerval val;
val.it_value.tv_sec = 30; //Timer 30 Seconds
val.it_value.tv_usec = 0;
val.it_interval = val.it_value;
setitimer(ITIMER_PROF, &val, NULL);
}
int main()
{
/*Set the handler for the signal SIG to HANDLER */
signal(SIGINT, signal_handler);
init_sigaction();
init_time();
Some_other_function();
}
Now I am using some other function, and I want to pause sigaction timer until other function's execution. how can I implemented interrupt for pause?
Thanks,

Answer 1

From the manual page of setitimer:
A timer which is set to zero (it_value is zero or the timer expires and it_interval is zero) stops.
Call setitimer with zero times, and with a valid old_value argument to store the current values of the timer, so you can start it again later.
Edit:
How about something like this:
struct itimerval old_timer;
void pause_timer()
{
struct itimerval zero_timer = { 0 };
setitimer(ITIMER_PROF, &zero_time, &old_timer);
}
void resume_timer()
{
setitimer(ITIMER_PROF, &old_timer, NULL);
}
Note The code above is untested, and coded only by reading the manual page.

Answer 2

You could consider blocking some signals with e.g. the sigprocmask(2) system call.
However, I strongly recommend reading several times the signal(7) man page. Don't forget that a signal handler can happen any time (including at the worst possible time, e.g. during calls to fprintf or malloc...), so can only call directly or indirectly async-signal-safe functions; and a big lot of library functions are not in this small restricted set. A usual way is to set a volatile sig_atomic_t flag in the signal handler, and test for it outside.