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 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)

GNU                                                                            2021-03-22                                                                       SLEEP(3)