sleep - sleep for a specified number of seconds

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 │
       └─────────────────────────────────────────────────────────┴───────────────┴─────────────────────────────┘

Caveats

       Using longjmp(3) from a signal handler or modifying the handling of SIGALRM  while  sleeping  will  cause
       undefined results.

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.

History

       POSIX.1-2001.

Library

       Standard C library (libc, -lc)

Name

       sleep - sleep for a specified number of seconds

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.

Standards

       POSIX.1-2008.

Synopsis

#include<unistd.h>unsignedintsleep(unsignedintseconds);

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.