Question

I am running some profiling tests, and usleep is an useful function. But while my program is sleeping, this time does not appear in the profile.

eg. if I have a function as :

void f1() {
    for (i = 0; i < 1000; i++)
        usleep(1000);
}

With profile tools as gprof, f1 does not seems to consume any time.

What I am looking is a method nicer than an empty while loop for doing an active sleep, like:

while (1) {
    if (gettime()  == whatiwant)
        break;
}

Answer 1

What kind of a system are you on? In UNIX-like systems you can use setitimer() to send a signal to a process after a specified period of time. This is the facility you would need to implement the type of “active sleep” you’re looking for.

Set the timer, then loop until you receive the signal.