Receiving

C | Fortran-2008

MPI_Status

Definition

MPI_Status represents the status of a reception operation, returned by receive operations (MPI_Recv), non-blocking operation wait (MPI_Wait, MPI_Waitall, MPI_Waitany and MPI_Waitsome) or test (MPI_Test, MPI_Testall, MPI_Testany and MPI_Testsome). In C the MPI_Status is a structure that contains at least 3 attributes: MPI_SOURCE, MPI_TAG and MPI_ERROR. There may be additional attributes that are implementation-specific. When the user has no use of the MPI_Status, they can pass the constant MPI_STATUS_IGNORE (or MPI_STATUSES_IGNORE for array of statuses).
In Fortran-90, the MPI status is represented with MPI_STATUS_SIZE.

Example

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#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>

/**
 * @brief Display information contained in the MPI_Status.
 **/
int main(int argc, char* argv[])
{
    MPI_Init(&argc, &argv);

    int my_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);

    if(my_rank == 0)
    {
        // The "master" MPI process issues the MPI_Bsend.
        int buffer_sent = 12345;
        int tag = 67890;
        printf("MPI process %d sends value %d with tag %d.\n", my_rank, buffer_sent, tag);
        MPI_Ssend(&buffer_sent, 1, MPI_INT, 1, tag, MPI_COMM_WORLD);
    }
    else
    {
        // The "slave" MPI process receives the message.
        int buffer_received;
        MPI_Status status;
        MPI_Recv(&buffer_received, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
        printf("MPI process %d received value %d from rank %d, with tag %d and error code %d.\n", 
               my_rank,
               buffer_received,
               status.MPI_SOURCE,
               status.MPI_TAG,
               status.MPI_ERROR);
    }

    MPI_Finalize();

    return EXIT_SUCCESS;
}