It is often desirable to wait on multiple requests. An example is a master/slave program, where the master waits for one or more slaves to send it a message.
MPI_Waitall(count, array_of_requests, array_of_statuses)
MPI_Waitany(count, array_of_requests, index, status)
MPI_Waitsome(incount, array_of_requests, outcount, array_of_indices, array_of_statuses)
There are corresponding versions of test for each of these.
127 The MPI_WAITSOME and MPI_TESTSOME may be used to implement master/slave algorithms that provide fair access to the master by the slaves.