/*
	proc 0 use MPI_Isend to send message,
	proc 1 use MPI_Irecv to receive message,
*/
#include<stdio.h>			// for input/output
#include<mpi.h>				//for mpi routines

#define BUFSIZE 2048		//The size of the messege being passed

main(int argc, char** argv)
{
	int rank;				//the rank of this process
	int i = 0;
	int tag = 0;
	int flag = 0;
	float *sendbuf, *recvbuf;
	MPI_Status status;		//not important here
	MPI_Request request;	//not important here

	sendbuf = (float *)malloc(sizeof(float)*BUFSIZE);
	recvbuf = (float *)malloc(sizeof(float)*BUFSIZE);

	MPI_Init(&argc, &argv);					//Initializing mpi
	MPI_Comm_rank(MPI_COMM_WORLD, &rank);	//Getting my rank

	if(rank == 0)
	{ 
		//sleep for 3 sec
		sleep(3);
		printf("Hello world! I am proc 0, sending to proc 1\n");
		//send to the proc 1
		MPI_Isend(sendbuf, BUFSIZE, MPI_FLOAT, 1, tag, MPI_COMM_WORLD, &request);
		MPI_Wait (&request, &status);
	}
	else if(rank == 1)
	{
		//recieve from the proc 0
		MPI_Irecv(recvbuf, BUFSIZE, MPI_FLOAT, 0, tag, MPI_COMM_WORLD, &request);
		do
		{
			printf("Wait %d\n", i++);
			MPI_Test (&request, &flag, &status);
		}
		while (flag == 0);
	}
	printf("Proc %d finished!!\n", rank);
	MPI_Finalize();
	free(sendbuf);
	free(recvbuf);
	return 0;
}