MPI_Irsend function

Initiates a ready mode send operation and returns a request handle that represents the communication operation.

Syntax

int MPIAPI MPI_Irsend(
  _In_opt_ void         *buf,
           int          count,
           MPI_Datatype datatype,
           int          dest,
           int          tag,
           MPI_Comm     comm,
  _Out_    MPI_Request  *request
);

Parameters

• buf [in, optional]
  A pointer to the buffer that contains the data to be sent. The buffer consists of count successive elements of the MPI_Datatype object that is indicated by the datatype handle. The message length is specified in terms of number of elements, not in number of bytes. The caller should not modify any part of the send buffer until the communication operation is completed.

• count
  The number of elements in the buffer array. If count is zero, the data part of the message is empty.

• datatype
  A handle that represents the data type of the elements in the buffer.

• dest
  The rank of the destination process within the communicator comm parameter.

• tag
  The message tag that is used to distinguish different types of messages.

• comm
  The handle to the communicator.

• request [out]
  On return, a pointer to a handle that represents the communication operation.

Return value

Returns MPI_SUCCESS on success. Otherwise, the return value is an error code.

In Fortran, the return value is stored in the IERROR parameter.

Fortran

    MPI_IRSEND(BUF, COUNT, DATATYPE, DEST, TAG, COMM, REQUEST, IERROR)
        <type> BUF(*)
        INTEGER COUNT, DATATYPE, DEST, TAG, COMM, REQUEST, IERROR

Remarks

This function can return before the message was copied out of the send buffer. This function is local, it returns immediately, irrespective of the status of other processes. See the remarks for the MPI_Rsend function for the description of the ready communication mode.

Requirements

See also

MPI Point to Point Functions

MPI_Rsend

MPI_Recv

MPI_Irecv

MPI_Wait

MPI_Test

MPI_Comm

MPI_Datatype