usleep(3C) Standard C Library Functions usleep(3C)NAME
usleep - suspend execution for interval in microseconds
SYNOPSIS
#include <unistd.h>
int usleep(useconds_t useconds);
DESCRIPTION
The usleep() function suspends the caller from execution for the number of microseconds specified by the useconds argument. The actual sus-
pension time might be less than requested because any caught signal will terminate usleep() following execution of that signal's catching
routine. The suspension time might be longer than requested by an arbitrary amount because of the scheduling of other activity in the sys-
tem.
If the value of useconds is 0, then the call has no effect.
The use of the usleep() function has no effect on the action or blockage of any signal. In a multithreaded process, only the invoking
thread is suspended from execution.
RETURN VALUES
On completion, usleep() returns 0. There are no error retruns.
ERRORS
No errors are returned.
USAGE
The usleep() function is included for its historical usage. The nanosleep(3C) function is preferred over this function.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Committed |
+-----------------------------+-----------------------------+
|MT-Level |Safe |
+-----------------------------+-----------------------------+
|Standard |See standards(5). |
+-----------------------------+-----------------------------+
SEE ALSO nanosleep(3C), sleep(3C), attributes(5), standards(5)SunOS 5.11 5 Feb 2008 usleep(3C)
Check Out this Related Man Page
usleep(2) System Calls Manual usleep(2)NAME
usleep - suspend execution for an interval
SYNOPSIS DESCRIPTION
The function will cause the calling thread to be suspended from execution until either the number of real-time microseconds specified 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 activities by the system, or because of the time spent in
processing the call.
The useconds argument must be less than 1,000,000. If the value of useconds is 0, then the call has no effect.
If a signal is generated for the calling process during execution of and if the signal is being ignored or blocked from delivery, it is
unspecified whether returns when the signal is scheduled; if the signal is being blocked, it is also unspecified whether it remains pending
after returns or it is discarded.
If a signal is generated for the calling process during execution of except as a result of a prior call to and if the signal is not being
ignored or blocked from delivery, it is unspecified whether that signal has any effect other than causing to return.
If a signal-catching function interrupts and examines or changes either the time a is scheduled to be generated, the action associated with
the signal, or whether the signal is blocked from delivery, the results are unspecified.
If a signal-catching function interrupts and calls or to restore an environment saved prior to the call, the action associated with the
signal and the time at which a signal is scheduled to be generated are unspecified, it is also unspecified whether the signal is blocked,
unless the process's 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 will be rounded up to the next supported value.
Interactions between and any of the following are unspecified:
RETURN VALUE
On successful completion, returns 0. Otherwise, it returns -1 and sets to indicate the error.
ERRORS
The function may fail if:
[EINVAL] The time interval specified 1,000,000 or more microseconds.
APPLICATION USAGE
The function is included for its historical usage. The function is preferred over this function. Multi-threaded applications are recom-
mended to use instead of is also a thread canceling point.
SEE ALSO alarm(2), getitimer(2), nanosleep(2), sigaction(2), sleep(3C), timer_create(2), timer_delete(2), timer_getoverrun(2), timer_gettime(2),
timer_settime(2), <unistd.h>.
CHANGE HISTORY
First released in Issue 4, Version 2.
usleep(2)