1 .\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
3 .\" %%%LICENSE_START(VERBATIM)
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
6 .\" preserved on all copies.
8 .\" Permission is granted to copy and distribute modified versions of this
9 .\" manual under the conditions for verbatim copying, provided that the
10 .\" entire resulting derived work is distributed under the terms of a
11 .\" permission notice identical to this one.
13 .\" Since the Linux kernel and libraries are constantly changing, this
14 .\" manual page may be incorrect or out-of-date. The author(s) assume no
15 .\" responsibility for errors or omissions, or for damages resulting from
16 .\" the use of the information contained herein. The author(s) may not
17 .\" have taken the same level of care in the production of this manual,
18 .\" which is licensed free of charge, as they might when working
21 .\" Formatted or processed versions of this manual, if unaccompanied by
22 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" Modified Sat Jul 24 18:16:02 1993 by Rik Faith (faith@cs.unc.edu)
26 .TH SLEEP 3 2021-03-22 "GNU" "Linux Programmer's Manual"
28 sleep \- sleep for a specified number of seconds
31 .B #include <unistd.h>
33 .BI "unsigned int sleep(unsigned int " "seconds" );
37 causes the calling thread to sleep either until
38 the number of real-time seconds specified in
40 have elapsed or until a signal arrives which is not ignored.
42 Zero if the requested time has elapsed,
43 or the number of seconds left to sleep,
44 if the call was interrupted by a signal handler.
46 For an explanation of the terms used in this section, see
54 Interface Attribute Value
57 T} Thread safety MT-Unsafe sig:SIGCHLD/linux
63 POSIX.1-2001, POSIX.1-2008.
71 man page for a discussion of the clock used.
75 may be implemented using
79 (POSIX.1 permits this);
88 from a signal handler or modifying the handling of
90 while sleeping will cause undefined results.