Calling function every 3 sec

Question

I have a problem with timer in C. I have to call a function every 3 sec (for e.g. To put down Hello world! every 3 sec). It must not wait on calling function. I'm doing a game, so function will be used to make random coordinates, but I must be able to move my player around.

Any hints?

A second thread that blocks for three seconds is needed. – Fiddling Bits Jan 19 '14 at 18:02 — Fiddling Bits, Jan 19 '14 at 18:02
Read about; `sigaction()`, `alarm()` and `write()`. – alk Jan 19 '14 at 18:23 — alk, Jan 19 '14 at 18:23
Have you tried using the sleep function – Ed Heal Jan 19 '14 at 18:24 — Ed Heal, Jan 19 '14 at 18:24
No i hav not tried sleep function. I ll look about it. – user2942681 Jan 19 '14 at 18:38 — user2942681, Jan 19 '14 at 18:38
Sleep function is not working. I stop whol program! – user2942681 Jan 19 '14 at 18:58 — user2942681, Jan 19 '14 at 18:58

score 1 · Accepted Answer · answered Jan 19 '14 at 18:34

1

If you are in a Linux enviornment, you could consider something like this:

void hello_word_func(int signum)
{
    printf ("Hello World!\n");
    signal (SIGALRM, hello_word_func);
    alarm (3);
}

signal (SIGALRM, hello_word_func);
alarm (3);

Another option, which will eat more of your CPU's resources (busy-wait) is to spawn a new thread, and issue a loop of outputting "Hello World" and sleeping for 3 seconds.

answered Jan 19 '14 at 18:34

Yarel

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`sleep` from `` does not busy wait. – lbolla Jan 19 '14 at 19:21
You're right. My mistake. – Yarel Jan 19 '14 at 20:24
`printf()` (along with lots of other functions) is not async signal safe. Use `write(fileno(stdout), ...)` to print to `stdout` instead. – alk Jan 20 '14 at 13:24

Calling function every 3 sec

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