sleep

SLEEP(3)                   Linux Programmer's Manual                  SLEEP(3)

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  at-
       tributes(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 5.05 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/.

GNU                               2017-09-15                          SLEEP(3)