#include <unistd.h> unsigned int sleep(unsigned int seconds);
LIBRARY
Standard C library (libc, -lc)
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
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.
STANDARDS
POSIX.1-2008.
HISTORY
POSIX.1-2001.
CAVEATS
Using longjmp(3) from a signal handler or modifying the
handling of SIGALRM while sleeping will cause undefined results.