One-sided communication 2

mpi_put_2.c

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

#define WORKER(id) if (ID == (id))
#define MASTER WORKER(0)

int main(int argc, char *argv[])
{
	int numprocs, ID;
	int next, prev;
	int *buf;
	MPI_Win win;

	MPI_Init(&argc, &argv);
	MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
	MPI_Comm_rank(MPI_COMM_WORLD, &ID);
	next = (ID + 1) % numprocs;
	prev = (ID - 1 + numprocs) % numprocs;

	MPI_Alloc_mem(sizeof(int), MPI_INFO_NULL, &buf);
	*buf = 0;

	MPI_Win_create(buf, sizeof(int), 1, MPI_INFO_NULL, MPI_COMM_WORLD, &win);

	MPI_Win_lock(MPI_LOCK_EXCLUSIVE, next, 0, win);
	MPI_Put(&ID, 1, MPI_INT, next, 0, 1, MPI_INT, win);
	MPI_Win_unlock(next, win);
	
	MPI_Barrier(MPI_COMM_WORLD);
	
	printf("Worker %d: %d\n", ID, *buf);

	MPI_Win_free(&win);

	MPI_Free_mem(buf);

	MPI_Finalize();

	return 0;
}