sleep - sleep for a specified number of seconds
#include <unistd.h>
unsigned int sleep(unsigned int seconds);
sleep() 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(7).
| Interface |
Attribute |
Value |
| sleep () |
Thread safety |
MT-Unsafe sig:SIGCHLD/linux |
POSIX.1-2001, POSIX.1-2008.
On Linux,
sleep() is implemented via
nanosleep(2). See the
nanosleep(2) man page for a discussion of the clock used.
On some systems,
sleep() may be implemented using
alarm(2) and
SIGALRM (POSIX.1 permits this); mixing calls to
alarm(2) and
sleep() is a bad idea.
Using
longjmp(3) from a signal handler or modifying the handling of
SIGALRM while sleeping will cause undefined results.
sleep(1),
alarm(2),
nanosleep(2),
signal(2),
signal(7)