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order, nonblocking, order Nonblocking communication operations are ordered according to the execution order of the posting calls. The non-overtaking requirement of Section gif is extended to nonblocking communication.


The order requirement specifies how post-send calls are matched to post-receive calls. There are no restrictions on the order in which operations complete. Consider the code in Example gif.


Since the completion of a receive can take an arbitrary amount of time, there is no way to infer that the receive operation completed, short of executing a complete-receive call. On the other hand, the completion of a send operation can be inferred indirectly from the completion of a matching receive.

Jack Dongarra
Fri Sep 1 06:16:55 EDT 1995