usleep - suspend process for defined interval

Syntax

#include <unistd.h> int usleep(useconds_t useconds);

Description  Suspends the current process for useconds microseconds. The actual length of time for

	which the process is suspended can be longer than useconds microseconds due to other activities in the system or because of the time required for processing the call. useconds must be < 1 000 000. If useconds = 0, then usleep() has no effect. The routine is implemented by setting the interval timer of the process and then waiting until it expires. The previous status of the timer is saved and restored. If the wait time or ’sleep time’ exceeds the period until expiry of the previous timer, the process is only suspended until the signal would have occurred, and the signal is sent shortly before this sleep time expires. If threads are used, then the function affects the process or a thread in the following manner: usleep() causes the current thread to be suspended until a specified time expires or a signal is sent to the thread.
Return val.	0 -1	if successful. otherwise.
Notes See also	usleep() is supported for historical reasons. setitimer() should be used instead. alarm(), getitimer(), sigaction(), sleep(), unistd.h.