Send-Receive
[Point-to-Point Communication]

Collaboration diagram for Send-Receive:

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Detailed Description

The send-receive operations combine in one call the sending of a message to one destination and the receiving of another message, from another process.

A message sent by a send-receive operation can be received by a regular receive operation or probed by a probe operation; a send-receive operation can receive a message sent by a regular send operation.

Functions
int	MOC_Sendrecv (void *sendbuf, int sendcount, MOC_Datatype sendtype, int dest, int sendtag, void *recvbuf, int recvcount, MOC_Datatype recvtype, int source, int recvtag, MOC_Comm comm, MOC_Status *status)
	Execute a blocking send and receive operation.
int	MOC_Sendrecv_replace (void *buf, int count, MOC_Datatype datatype, int dest, int sendtag, int source, int recvtag, MOC_Comm comm, MOC_Status *status)
	Execute a blocking send and receive.

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Function Documentation

int MOC_Sendrecv	(	void *	sendbuf,
		int	sendcount,
		MOC_Datatype	sendtype,
		int	dest,
		int	sendtag,
		void *	recvbuf,
		int	recvcount,
		MOC_Datatype	recvtype,
		int	source,
		int	recvtag,
		MOC_Comm	comm,
		MOC_Status *	status
	)

Execute a blocking send and receive operation.

Both send and receive use the same communicator, but possibly different tags. The send buffer and receive buffers may be disjoint, and may have different lengths and datatypes.

Parameters:

	sendbuf	in Pointer to buffer where data is stored
	sendcount	in Number of elements to be send (not equal to actual byte-value)
	sendtype	in Type of elements to be send
	dest	in Rank of receiving process
	sendtag	in Tag of message to be send
	recvbuf	inout Buffer into which data should be stored
	recvcount	in Number of elements in receive buffer (not equal to actual byte-value)
	recvtype	in Datatype of each receive buffer element
	source	in Rank of source
	recvtag	in Tag of message to be received
	comm	in Communicator of message
	status	inout Object holding status-information (has to be allocated by user)

Return values:

	MOC_SUCCESS	No error; MPI routine completed successfully.
	...	error-code

int MOC_Sendrecv_replace	(	void *	buf,
		int	count,
		MOC_Datatype	datatype,
		int	dest,
		int	sendtag,
		int	source,
		int	recvtag,
		MOC_Comm	comm,
		MOC_Status *	status
	)

Execute a blocking send and receive.

The same buffer is used both for the send and for the receive, so that the message sent is replaced by the message received.

Parameters:

	buf	inout Pointer to buffer
	count	in Number of elements (not equal to actual byte-value)
	datatype	in Type of elements
	dest	in Rank of receiving process
	sendtag	in Tag of message to be send
	source	in Rank of source
	recvtag	in Tag of message to be received
	comm	in Communicator of message
	status	inout Object holding status-information (has to be allocated by user)

Return values:

	MOC_SUCCESS	No error; MPI routine completed successfully.
	...	error-code