Call function periodically without using threads and sleep() method in c

Question

I want to call a function, let’s say every 10 or 20 seconds. When I searched, I came up with threads and the sleep() method everywhere.

I also checked for time and clock classes in C, but I could not find anything helpful specific to my question.

What is the simplest way to call functions periodically?

Answer 1

Using libevent, in my opinion, is the cleaner solution because, in the meantime, you can do other operations (even other timed functions).

Look at this simple and self-explanatory example that print out Hello every three seconds:

#include <stdio.h>
#include <sys/time.h>
#include <event.h>

void say_hello(int fd, short event, void *arg)
{
  printf("Hello\n");
}

int main(int argc, const char* argv[])
{
  struct event ev;
  struct timeval tv;

  tv.tv_sec = 3;
  tv.tv_usec = 0;

  event_init();
  evtimer_set(&ev, say_hello, NULL);
  evtimer_add(&ev, &tv);
  event_dispatch();

  return 0;
}