_barrier_spin(3synch)
_barrier_spin --
spin-wait at a barrier
Synopsis
cc [options] -Kthread file
#include <synch.h>
int _barrier_spin(barrier_spin_t *barrier);
Description
_barrier_spin makes the calling thread busy-wait, or spin,
at a spinning barrier
until count threads reach the barrier.
count is defined during initialization with _barrier_spin_init.
A thread is said to have reached the barrier
when it calls _barrier_spin.
When the last thread reaches the barrier,
all count spinning threads are released
from the barrier and allowed to resume execution.
The barrier is reset after the waiting threads are released.
barrier must previously have been initialized
(see barrier_spin_init(3synch)).
Parameters
barrier-
pointer to the barrier object at which to spin
Return values
_barrier_spin returns zero for success
and an error number for failure, as described below.
Errors
If the following condition is detected,
_barrier_spin returns the corresponding value:
EINVAL-
invalid argument specified
Usage
Because spinning barriers waste resources,
most applications should use blocking barriers
instead of spinning barriers.
Spinning barriers should only be used when
all participating threads will reach the barrier
at approximately the same time.
Warnings
Spinning barriers should never be used on a single processor system.
References
Intro(3synch),
_barrier_spin_destroy(3synch),
_barrier_spin_init(3synch),
barrier(3synch),
barrier_destroy(3synch),
barrier_init(3synch),
barrier_wait(3synch)
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004