SLEEP
Section: Linux Programmer's Manual (3)
Updated: 2017-09-15
Page Index
NAME
sleep - sleep for a specified number of seconds
SYNOPSIS
#include <unistd.h>
unsigned int sleep(unsigned int seconds);
DESCRIPTION
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.
RETURN VALUE
Zero if the requested time has elapsed,
or the number of seconds left to sleep,
if the call was interrupted by a signal handler.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
sleep()
| Thread safety | MT-Unsafe sig:SIGCHLD/linux
|
CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
NOTES
On Linux,
sleep()
is implemented via
nanosleep(2).
See the
nanosleep(2)
man page for a discussion of the clock used.
Portability notes
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.
SEE ALSO
sleep(1),
alarm(2),
nanosleep(2),
signal(2),
signal(7)
COLOPHON
This page is part of release 5.10 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.