sleep(3)                   Library Functions Manual                   sleep(3)

NAME
       sleep - sleep for a specified number of seconds

LIBRARY
       Standard C library (libc, -lc)

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 |
       +------------------------+---------------+-----------------------------+
VERSIONS
       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.

STANDARDS
       POSIX.1-2008.

HISTORY
       POSIX.1-2001.

CAVEATS
       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)

Linux man-pages 6.7               2023-10-31                          sleep(3)