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C | Fortran-2008 | Fortran-90

MPI_Comm_rank

Parameters

communicator

The MPI communicator to explore.

rank

A pointer on the variable in which write the rank of the calling MPI process in the MPI communicator given.

Return value

The error code returned from the communicator rank retrieval.

MPI_SUCCESS
The routine successfully completed.

Example

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

/**
 * @brief For each process in the default communicator MPI_COMM_WORLD, show their rank.
 **/
int main(int argc, char* argv[])
{
    MPI_Init(&argc, &argv);

    int my_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);

    printf("I am MPI process %d.\n", my_rank);

    MPI_Finalize();

    return EXIT_SUCCESS;
}