#define large 128
#include "mpi.h"
#include <stdio.h>
int main(argc, argv)
int argc;
char **argv;
{
    int rank, size, i, sbuf = 1, cnt;

    MPI_Init( &argc, &argv );
    MPI_Comm_rank( MPI_COMM_WORLD, &rank );
    MPI_Comm_size( MPI_COMM_WORLD, &size );
    if (rank == 0) {
	MPI_Request requests[large];
	MPI_Status  statuses[large];
	int         indices[large];
	int         buf[large];
	int         j, ndone;

	cnt = (size-1)*100;
	for (i=1; i<size; i++) 
	    MPI_Irecv( buf+i, 1, MPI_INT, i,
		       MPI_ANY_TAG, MPI_COMM_WORLD, &requests[i-1] );
	while(cnt > 0) {
	    MPI_Waitsome( size-1, requests, &ndone, indices, statuses );
	    for (i=0; i<ndone; i++) {
		j = indices[i];
		printf( "Msg from %d with tag %d\n", 
			statuses[i].MPI_SOURCE, 
			statuses[i].MPI_TAG );
		MPI_Irecv( buf+j, 1, MPI_INT, j+1,
			   MPI_ANY_TAG, MPI_COMM_WORLD, &requests[j] );
	    }
	    cnt -= ndone;
	}
	/* We should really cancel the pending receives */
	for (i=0; i<size-1; i++) 
	    MPI_Cancel( &requests[i] );
    }
    else {
	for (i=0; i<100; i++) 
	    MPI_Send( &sbuf, 1, MPI_INT, 0, i, MPI_COMM_WORLD );
    }
    MPI_Finalize();
    return 0;
}