MPI_BSEND_INIT, MPI_Bsend_init

Purpose

Creates a persistent buffered mode send request.

C synopsis

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

C++ synopsis

#include mpi.h
MPI::Prequest MPI::Comm::Bsend_init(const void* buf, int count,
                                    const MPI::Datatype& datatype,
                                    int dest, int tag) const;

FORTRAN synopsis

include 'mpif.h' or use mpi
MPI_BSEND_INIT(CHOICE BUF,INTEGER COUNT,INTEGER DATATYPE,
      INTEGER DEST,INTEGER TAG,INTEGER COMM,INTEGER REQUEST,
      INTEGER IERROR)

Description

This subroutine creates a persistent communication request for a buffered
mode send operation. MPI_START or MPI_STARTALL must be called to activate
the send.

Because it is the MPI_START that initiates communication, any error related
to insufficient buffer space occurs at the MPI_START.

Parameters

buf
     is the initial address of the send buffer (choice) (IN)
count
     is the number of elements to be sent (integer) (IN)
datatype
     is the type of each element (handle) (IN)
dest
     is the rank of the destination task (integer) (IN)
tag
     is the message tag (positive integer) (IN)
comm
     is the communicator (handle) (IN)
request
     is the communication request (handle) (OUT)
IERROR
     is the FORTRAN return code. It is always the last argument.

Notes

Make sure you have enough buffer space available. An error occurs if the
message must be buffered and there is there is not enough buffer space. The
amount of buffer space needed to be safe depends on the expected peak of
pending messages. The sum of the sizes of all of the pending messages at
that point plus (MPI_BSEND_INIT_OVERHEAD*number_of_messages) should be
sufficient.

Avoid using MPI_BSEND_INIT if possible. It adds overhead because it
requires an extra memory-to-memory copy of the outgoing data. If
MPI_BSEND_INIT is used, the associated receive operations may perform
better with MPI_CSS_INTERRUPT enabled.

Errors

Invalid count
     count < 0

Invalid datatype

Type not committed

Invalid destination
     dest < 0 or dest > = groupsize

Invalid tag
     tag < 0

Invalid comm

MPI not initialized

MPI already finalized

Related information

     MPI_IBSEND
     MPI_START