BARRIER(3) BSD Library Functions Manual BARRIER(3)
NAME
OSMemoryBarrier -- memory barrier to order loads and stores
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <libkern/OSAtomic.h>
void
OSMemoryBarrier(void);
DESCRIPTION
OSMemoryBarrier() strictly orders memory accesses in a weakly ordered memory model such as with PowerPC, by creating a barrier. All loads
and stores executed in sequential program order before the barrier will complete with respect to the memory coherence mechanism, before any
load or store executed after the barrier. Used with an atomic operation, the barrier can be used to create custom synchronization protocols
as an alternative to the spinlock or queue/dequeue operations. Note that this barrier does not order uncached loads and stores. On a
uniprocessor, the barrier operation is typically optimized into a nop.
SEE ALSO
atomic(3), spinlock(3)
Darwin May 26, 2004 Darwin
