1SLEEP(3) Linux Programmer's Manual SLEEP(3)
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6 sleep - sleep for a specified number of seconds
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9 #include <unistd.h>
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11 unsigned int sleep(unsigned int seconds);
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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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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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23 For an explanation of the terms used in this section, see
24 attributes(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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33 POSIX.1-2001, POSIX.1-2008.
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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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48 sleep(1), alarm(2), nanosleep(2), signal(2), signal(7)
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51 This page is part of release 4.15 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 2017-09-15 SLEEP(3)