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BARRIER(3)               BSD Library Functions Manual               BARRIER(3)

     OSMemoryBarrier -- memory barrier to order loads and stores

     Standard C Library (libc, -lc)

     #include <libkern/OSAtomic.h>


     OSMemoryBarrier() strictly orders memory accesses in a weakly ordered memory model such as with Pow-erPC, PowerPC,
     erPC, by creating a barrier.  All loads and stores executed in sequential program order before the bar-rier barrier
     rier 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 synchro-nization synchronization
     nization protocols as an alternative to the spinlock or queue/dequeue operations.  Note that this bar-rier barrier
     rier does not order uncached loads and stores.  On a uniprocessor, the barrier operation is typically
     optimized into a nop.

     atomic(3), spinlock(3)

Darwin                           May 26, 2004                           Darwin

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