05-27-2008
andryk is right - alarm timer expiry (SIGALRM) will be delivered to the process, but only when the process has enough priority to be awakened. In other words, if you ask for 10ms sleep time on a busy system, your alarm will be instantiated after 10ms, guaranteed, but the time when your process gets a turn at the CPU is NOT guaranteed, unless your process has elevated (realtime) priority. You have to wait for other processes to give up the CPU before you get it back, and process the signal. This becomes a problem on a busy system, or when the duration of the wait is less than a quantum slice and there is a least one other process that needs the cpu.
I really don't recommend it, but on a busy system you may have to nice your program up to a very high prioity to get the results you asked for.
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LEARN ABOUT OPENSOLARIS
sleep
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
cc(1B), 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 5.11 30 Oct 2007 sleep(3UCB)