sleep(3) [osx man page]

SLEEP(3)						   BSD Library Functions Manual 						  SLEEP(3)

NAME

     sleep -- suspend thread execution for an interval measured in seconds

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     unsigned int
     sleep(unsigned int seconds);

DESCRIPTION

     The sleep() function suspends execution of the calling thread until either seconds seconds have elapsed or a signal is delivered to the
     thread and its action is to invoke a signal-catching function or to terminate the thread or process.  System activity may lengthen the sleep
     by an indeterminate amount.

     This function is implemented using nanosleep(2) by pausing for seconds seconds or until a signal occurs.  Consequently, in this implementa-
     tion, sleeping has no effect on the state of process timers, and there is no special handling for SIGALRM.

RETURN VALUES

     If the sleep() function returns because the requested time has elapsed, the value returned will be zero.  If the sleep() function returns due
     to the delivery of a signal, the value returned will be the unslept amount (the requested time minus the time actually slept) in seconds.

SEE ALSO

     nanosleep(2), usleep(3)

STANDARDS

     The sleep() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'').

HISTORY

     A sleep() function appeared in Version 7 AT&T UNIX.

BSD
								 February 13, 1998							       BSD

USLEEP(3)						   BSD Library Functions Manual 						 USLEEP(3)

NAME

     usleep -- suspend thread execution for an interval measured in microseconds

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     int
     usleep(useconds_t useconds);

DESCRIPTION

     The usleep() function suspends execution of the calling thread until either useconds microseconds have elapsed or a signal is delivered to
     the thread whose action is to invoke a signal-catching function or to terminate the thread or process.  The actual time slept may be longer,
     due to system latencies and possible limitations in the timer resolution of the hardware.

     This function is implemented, using nanosleep(2), by pausing for useconds microseconds or until a signal occurs.  Consequently, in this
     implementation, sleeping has no effect on the state of process timers and there is no special handling for SIGALRM.

RETURN VALUES

     The usleep() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate
     the error.

ERRORS

     The usleep() function will fail if:

     [EINTR]		A signal was delivered to the process and its action was to invoke a signal-catching function.

SEE ALSO

     nanosleep(2), sleep(3)

HISTORY

     The usleep() function appeared in 4.3BSD.

BSD
								 February 13, 1998							       BSD