the barrier. On a uniprocessor, the barrier operation is typically a nop.
On a multiprocessor, the barrier can be quite expensive.
.Pp
-Most code will want to use the barrier functions to insure that memory shared
+Most code will want to use the barrier functions to ensure that memory shared
between threads is properly synchronized. For example, if you want to initialize
a shared data structure and then atomically increment a variable to indicate
that the initialization is complete, then you must use OSAtomicIncrement32Barrier()