usleep

Quoted 1 line

Any way... what is setrealtime? I dont have it on my linux machine

it's a simple tool I wrote a long time ago, code below. ***** N O T E *******
it can effectively freeze your machine, since it gives you a process which will not be prempted! it *is* useful, though, if you know what you're doing...
***** N O T E *******

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sched.h>
/* setrealtime: run procs in realtime.
author: Mark Hahn <[email protected]> */

int main(int argc, char *argv[]) {
    static struct sched_param sched_parms;
    int pid, wrapper=0;

    if (argc <= 1)
        return 1;

    pid = atoi(argv[1]);

    if (!pid || argc != 2) {
        wrapper = 1;
        pid = getpid();
    }
    if (!pid)
        return 1;
 
    sched_parms.sched_priority = sched_get_priority_min(SCHED_FIFO);
    if (sched_setscheduler(pid, SCHED_FIFO, &sched_parms) == -1) {
        perror("cannot set realtime scheduling policy");
        return 1;
    }
    if (wrapper) {
        setuid(getuid());
        execvp(argv[1],&argv[1]);
        perror("exec failed");
        return 1;
    }
    return 0;
}