sleep - sleep for a specified number of seconds
unsigned int sleep(unsigned int seconds);
() causes the calling thread to sleep either until the number of
real-time seconds specified in seconds
have elapsed or until a signal
arrives which is not ignored.
Zero if the requested time has elapsed, or the number of seconds left to sleep,
if the call was interrupted by a signal handler.
For an explanation of the terms used in this section, see attributes
On Linux, sleep
() is implemented via nanosleep
(2). See the
(2) man page for a discussion of the clock used.
On some systems, sleep
() may be implemented using alarm
(POSIX.1 permits this); mixing calls to alarm
() is a bad idea.
(3) from a signal handler or modifying the handling of
while sleeping will cause undefined results.