1SLEEP(3)                   Linux Programmer's Manual                  SLEEP(3)
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NAME

6       sleep - sleep for a specified number of seconds
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SYNOPSIS

9       #include <unistd.h>
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11       unsigned int sleep(unsigned int seconds);
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DESCRIPTION

14       sleep()  causes  the calling thread to sleep either until the number of
15       real-time seconds specified in seconds have elapsed or until  a  signal
16       arrives which is not ignored.
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RETURN VALUE

19       Zero  if  the requested time has elapsed, or the number of seconds left
20       to sleep, if the call was interrupted by a signal handler.
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ATTRIBUTES

23       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
24       tributes(7).
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26       ┌────────────────────────┬───────────────┬─────────────────────────────┐
27       │Interface               │ Attribute     │ Value                       │
28       ├────────────────────────┼───────────────┼─────────────────────────────┤
29       │sleep()                 │ Thread safety │ MT-Unsafe sig:SIGCHLD/linux │
30       └────────────────────────┴───────────────┴─────────────────────────────┘
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CONFORMING TO

33       POSIX.1-2001, POSIX.1-2008.
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NOTES

36       On   Linux,   sleep()   is   implemented  via  nanosleep(2).   See  the
37       nanosleep(2) man page for a discussion of the clock used.
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39   Portability notes
40       On some systems, sleep() may be implemented using alarm(2) and  SIGALRM
41       (POSIX.1  permits  this); mixing calls to alarm(2) and sleep() is a bad
42       idea.
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44       Using longjmp(3) from a signal handler or  modifying  the  handling  of
45       SIGALRM while sleeping will cause undefined results.
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SEE ALSO

48       sleep(1), alarm(2), nanosleep(2), signal(2), signal(7)
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COLOPHON

51       This  page  is  part of release 5.12 of the Linux man-pages project.  A
52       description of the project, information about reporting bugs,  and  the
53       latest     version     of     this    page,    can    be    found    at
54       https://www.kernel.org/doc/man-pages/.
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58GNU                               2021-03-22                          SLEEP(3)
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