program main
	include 'mpif.h'
	parameter (BUFSIZE = 2048)
	integer ierr, rank
	integer tag, status(MPI_STATUS_SIZE)
	integer size, messagesize
	real message(BUFSIZE)
	real BUFFER*(*)

	call MPI_INIT(ierr)
	call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
	tag = 0
	messagesize = BUFSIZE
	if (rank == 0) then
		print *, 'Hello world! I am proc ', rank,
	1	', sending to proc 1..'
		size = BUFSIZE * 4 + MPI_BSEND_OVERHEAD
		call MPI_BUFFER_ATTACH(BUFFER, size, ierr)
C
C               The buffer size in MPI_BSEND must be interger
C               If you put a parameter in it, eg.BUFSIZE, it will cause error
C
		call MPI_BSEND(message, messagesize, MPI_REAL,
	1	1, tag, MPI_COMM_WORLD, ierr)
		call MPI_BUFFER_DETACH(BUFFER, size, ierr)
	else if (rank == 1) then
		call SLEEP(3)
		print *, 'Hello world! I am proc ', rank,
	1	', just wake up!!'
		call MPI_RECV(message, BUFSIZE, MPI_REAL,
	1	0, tag, MPI_COMM_WORLD, status, ierr)
		print *, 'Hello world! Received 1 message ',
	1	'proc 1!!'
	endif
	print *, 'Proc ', rank, ' finished!!'
	call MPI_FINALIZE(ierr)
	end