I would like a precision on the semantics of MPI_Waitany in this situation:

- Process 1 does 2 MPI_Irecv with different tags A and B (the order doesn't matter); it then waits on the two requests with MPI_Waitany.

- In the mean time, process 2 does an MPI_Send with tag A, then MPI_Send with tag B.

Can I ensure that MPI_Waitany will always give me the index of the message corresponding to the first MPI_Send, i.e. the one with the tag A, even in situations where process 1 called MPI_Irecv on a tag B first?

Thanks