Explain on your fingers - how to work with setitimer?

Question

linux

It is necessary to display the time every 0.5 seconds.
Can you humanly explain how to work with this call, what exactly the 2nd and 3rd arguments of the function mean and how to fill them in to solve my problem?

int setitimer(int which, const struct itimerval *value, struct itimerval *ovalue);

Answer 1

read man
In my opinion, a simpler option would be to use select. And set the waiting time in accordance with the value of the current time (so as not to accumulate an error).