sleep(3UCB) SunOS/BSD Compatibility Library Functions sleep(3UCB)NAME
sleep - suspend execution for interval
SYNOPSIS
/usr/ucb/cc [ flag ... ] file ...
int sleep( seconds);
unsigned seconds;
DESCRIPTION
sleep() suspends the current process from execution for the number of seconds specified by the argument. The actual suspension time may be
up to 1 second less than that requested, because scheduled wakeups occur at fixed 1-second intervals, and may be an arbitrary amount longer
because of other activity in the system.
sleep() is implemented by setting an interval timer and pausing until it expires. The previous state of this timer is saved and restored.
If the sleep time exceeds the time to the expiration of the previous value of the timer, the process sleeps only until the timer would have
expired, and the signal which occurs with the expiration of the timer is sent one second later.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|MT-Level |Async-Signal-Safe |
+-----------------------------+-----------------------------+
SEE ALSO alarm(2), getitimer(2), longjmp(3C), siglongjmp(3C), sleep(3C), usleep(3C), attributes(5)NOTES
Use of these interfaces should be restricted to only applications written on BSD platforms. Use of these interfaces with any of the system
libraries or in multi-thread applications is unsupported.
SIGALRM should not be blocked or ignored during a call to sleep(). Only a prior call to alarm(2) should generate SIGALRM for the calling
process during a call to sleep(). A signal-catching function should not interrupt a call to sleep() to call siglongjmp(3C) or longjmp(3C)
to restore an environment saved prior to the sleep() call.
WARNINGS
sleep() is slightly incompatible with alarm(2). Programs that do not execute for at least one second of clock time between successive
calls to sleep() indefinitely delay the alarm signal. Use sleep(3C). Each sleep(3C) call postpones the alarm signal that would have been
sent during the requested sleep period to occur one second later.
SunOS 5.10 12 Feb 1993 sleep(3UCB)
Check Out this Related Man Page
USLEEP(P) POSIX Programmer's Manual USLEEP(P)
NAME
usleep - suspend execution for an interval
SYNOPSIS
#include <unistd.h>
int usleep(useconds_t useconds);
DESCRIPTION
The usleep() function shall cause the calling thread to be suspended from execution until either the number of realtime microseconds speci-
fied by the argument useconds has elapsed or a signal is delivered to the calling thread and its action is to invoke a signal-catching
function or to terminate the process. The suspension time may be longer than requested due to the scheduling of other activity by the sys-
tem.
The useconds argument shall be less than one million. If the value of useconds is 0, then the call has no effect.
If a SIGALRM signal is generated for the calling process during execution of usleep() and if the SIGALRM signal is being ignored or blocked
from delivery, it is unspecified whether usleep() returns when the SIGALRM signal is scheduled. If the signal is being blocked, it is also
unspecified whether it remains pending after usleep() returns or it is discarded.
If a SIGALRM signal is generated for the calling process during execution of usleep(), except as a result of a prior call to alarm(), and
if the SIGALRM signal is not being ignored or blocked from delivery, it is unspecified whether that signal has any effect other than caus-
ing usleep() to return.
If a signal-catching function interrupts usleep() and examines or changes either the time a SIGALRM is scheduled to be generated, the
action associated with the SIGALRM signal, or whether the SIGALRM signal is blocked from delivery, the results are unspecified.
If a signal-catching function interrupts usleep() and calls siglongjmp() or longjmp() to restore an environment saved prior to the usleep()
call, the action associated with the SIGALRM signal and the time at which a SIGALRM signal is scheduled to be generated are unspecified. It
is also unspecified whether the SIGALRM signal is blocked, unless the process' signal mask is restored as part of the environment.
Implementations may place limitations on the granularity of timer values. For each interval timer, if the requested timer value requires a
finer granularity than the implementation supports, the actual timer value shall be rounded up to the next supported value.
Interactions between usleep() and any of the following are unspecified:
nanosleep()
setitimer()
timer_create()
timer_delete()
timer_getoverrun()
timer_gettime()
timer_settime()
ualarm()
sleep()
RETURN VALUE
Upon successful completion, usleep() shall return 0; otherwise, it shall return -1 and set errno to indicate the error.
ERRORS
The usleep() function may fail if:
EINVAL The time interval specified one million or more microseconds.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
Applications are recommended to use nanosleep() if the Timers option is supported, or setitimer(), timer_create(), timer_delete(),
timer_getoverrun(), timer_gettime(), or timer_settime() instead of this function.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
alarm() , getitimer() , nanosleep() , sigaction() , sleep() , timer_create() , timer_delete() , timer_getoverrun() , the Base Definitions
volume of IEEE Std 1003.1-2001, <unistd.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
online at http://www.opengroup.org/unix/online.html .
IEEE /The Open Group 2003 USLEEP(P)