One option is to use the gethostname(2) system call:
/* C Example */
#include <mpi.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
int main (int argc, char* argv[])
{
int rank, size;
int buffer_length = 512;
char hostname[buffer_length];
MPI_Init (&argc, &argv); /* starts MPI */
MPI_Comm_rank (MPI_COMM_WORLD, &rank); /* get current process id */
MPI_Comm_size (MPI_COMM_WORLD, &size); /* get number of processes */
gethostname(hostname, buffer_length); /* get hostname */
printf( "Hello world from process %d running on %s of %d\n", rank, hostname, size );
MPI_Finalize();
return 0;
}
Another is to use MPI_Get_processor_name:
/* C Example */
#include <mpi.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
int main (int argc, char* argv[])
{
int rank, size;
int buffer_length = MPI_MAX_PROCESSOR_NAME;
char hostname[buffer_length];
MPI_Init (&argc, &argv); /* starts MPI */
MPI_Comm_rank (MPI_COMM_WORLD, &rank); /* get current process id */
MPI_Comm_size (MPI_COMM_WORLD, &size); /* get number of processes */
MPI_Get_processor_name(hostname, &buffer_length); /* get hostname */
printf( "Hello world from process %d running on %s of %d\n", rank, hostname, size );
MPI_Finalize();
return 0;
}