USLEEP(3)

NAME
usleep - suspend execution for interval of microseconds

SYNOPSIS
#include <unistd.h>
void
usleep(u_int microseconds);

DESCRIPTION
The usleep() function suspends execution of the calling process for microseconds of time. System activity or time spent in processing the call may lengthen the sleep slightly.

If a timer is already running on the process its state is saved. If the value microseconds is more than or equal to the remaining clock time for the saved timer, the sleep time is set to the remaining clock time. The state of the previous timer is restored after microseconds has passed.

This routine is implemented using setitimer(2); it requires eight system calls each time it is invoked. A similar but less compatible function can be obtained with a single select(2); such a function would not restart after signals, but would not interfere with other uses of setitimer.

SEE ALSO
getitimer(2), setitimer(2), sigpause(2), alarm(3), sleep(3), ualarm(3)

HISTORY
The usleep() function appeared in 4.3BSD.