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C | FORTRAN-legacy | FORTRAN-2008

MPI_Comm_rank

Definition

MPI_Comm_rank gets the rank of the calling MPI process in the communicator given.

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int MPI_Comm_rank(MPI_Comm communicator,
                  int 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.

Returned 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;
}