Manpages - sleep.3

Table of Contents

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)

COLOPHON

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Author: dt

Created: 2022-02-21 Mon 11:56