Page Index
1. Short Description
2. Syntax
2.1. C syntax
2.2. C++ syntax
3. Parameters
3.1. Input
4. Description
5. Errors
6. See also

MPI_Send

Short Description

Performs a standard-mode blocking send.

Syntax

C syntax

#include <mpi.h>
int MPI_Send(void *buf, int count, MPI_Datatype datatype,
     int dest, int tag, MPI_Comm comm)

C++ syntax

#include <mpi.h>
void Comm::Send(const void* buf, int count, const Datatype& datatype,
     int dest, int tag) const

Parameters

Input

buf	Initial address of send buffer (choice).
count	Number of elements send (nonnegative integer).
datatype	Datatype of each send buffer element (handle).
dest	Rank of destination (integer).
tag	Message tag (integer).
comm	Communicator (handle).

Description

MPI_Send performs a standard-mode, blocking send. This means that until the message has been actually written to the output buffer, the sender cannot continue running the program.

(Click on the image to watch the animation)

An easy code of how to use it:

int main(int argc, char *argv[])
{
    int rank, size;
 
    MPI_Init(&argc, &argv); // We start the processes communication data
    MPI_Comm_size(MPI_COMM_WORLD, &size); // We get the total of processes
    MPI_Comm_rank(MPI_COMM_WORLD, &rank); // We get the rank of this process
 
    MPI_Send(&rank // reference to send data
    		,1 // number of elements we are sending
    		,MPI_INT // Datatype of each element
    		,rank+1 // Rank of destination process
    		,0 // tag
    		,MPI_COMM_WORLD); // Communicator used
    .
    .
    .
    MPI_Finalize();
    return 0;
}

Errors

MPI_SUCCESS	No error; MPI routine completed successfully.
MPI_ERR_COMM	Invalid communicator. A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank).
MPI_ERR_COUNT	Invalid count argument. Count arguments must be non-negative; a count of zero is often valid.
MPI_ERR_TYPE	Invalid datatype argument. May be an uncommitted MPI_Datatype (see MPI_Type_commit).
MPI_ERR_TAG	Invalid tag argument. Tags must be non-negative; tags in a receive (MPI_Recv, MPI_Irecv, MPI_Sendrecv, etc.) may also be MPI_ANY_TAG. The largest tag value is available through the the attribute MPI_TAG_UB.
MPI_ERR_RANK	Invalid source or destination rank. Ranks must be between zero and the size of the communicator minus one; ranks in a receive (MPI_Recv, MPI_Irecv, MPI_Sendrecv, etc.) may also be MPI_ANY_SOURCE.