Using MPI_Irecv and MPI_Test
#include "mpi.h"
#include <stdio.h>
int main(int argc, char *argv[])
{
int rank, numprocs, i, flag=0,working=0;
int buffer[2]={1,2}, buffer2[2]={3,4}, buffer3[2]={5,6};
MPI_Request request;
MPI_Status status;
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
if (rank==0) {
MPI_Irecv(buffer, 2, MPI_INT, 1, 123, MPI_COMM_WORLD, &request);
printf("0 buffer[0]=%i\n",buffer[0]);
MPI_Send(buffer3, 2, MPI_INT, 1, 1234, MPI_COMM_WORLD);
MPI_Test(&request, &flag, &status);
while (!flag) {
working=0;
for (i=0;i<100000;i++)working++;
printf("still testing\n");
MPI_Test(&request, &flag, &status);
}
printf("0 buffer[0]=%i\n",buffer[0]);
} else {
printf("1 buffer[0]=%i\n",buffer[0]);
MPI_Recv(buffer, 2, MPI_INT, 0, 1234, MPI_COMM_WORLD,MPI_STATUS_IGNORE);
printf("1 buffer[0]=%i\n",buffer[0]);
MPI_Send(buffer2, 2, MPI_INT, 0, 123, MPI_COMM_WORLD);
}
MPI_Finalize();
return 0;
}