Definition
MPI_ERROR is the member of the MPI_Status structure that contains the error code of the corresponding receive operation. Although in practice it has no use for a blocking receive (MPI_Recv) since the error code is returned directly by the routine, it does have uses for its non-blocking counterpart (MPI_Irecv) where the MPI_Status cannot be obtained until the MPI_Request collected is waited on (MPI_Wait, MPI_Waitall, MPI_Waitany, MPI_Waitsome) or tested (MPI_Test, MPI_Testall, MPI_Testany, MPI_Testsome).