MPI_Bsend(3OpenMPI)													       MPI_Bsend(3OpenMPI)

NAME

       MPI_Bsend - Basic send with user-specified buffering.

SYNTAX

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

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_BSEND(BUF, COUNT,DATATYPE, DEST, TAG, COMM, IERROR)
	    <type>    BUF(*)
	    INTEGER   COUNT, DATATYPE, DEST, TAG, COMM, IERROR

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

INPUT PARAMETERS

       buf	 Initial address of send buffer (choice).

       count	 Number of entries in send buffer (nonnegative integer).

       datatype  Datatype of each send buffer element (handle).

       dest	 Rank of destination (integer).

       tag	 Message tag (integer).

       comm	 Communicator (handle).

OUTPUT PARAMETER

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Bsend performs a buffered-mode, blocking send.

NOTES

       This  send  is  provided  as  a	convenience  function;	it allows the user to send messages without worrying about where they are buffered
       (because the user must have provided buffer space with MPI_Buffer_attach).

       In deciding how much buffer space to allocate, remember that the buffer space is not available for reuse by  subsequent	MPI_Bsends  unless
       you  are certain that the message has been received (not just that it should have been received).  For example, this code does not allocate
       enough buffer space:

	   MPI_Buffer_attach( b, n*sizeof(double) + MPI_BSEND_OVERHEAD );
	   for (i=0; i<m; i++) {
	       MPI_Bsend( buf, n, MPI_DOUBLE, ... );
	   }

       because only enough buffer space is provided for a single send, and the loop may start a second MPI_Bsend before the first is  done  making
       use of the buffer.

       In C, you can force the messages to be delivered by MPI_Buffer_detach( &b, &n ); MPI_Buffer_attach( b, n ); (The MPI_Buffer_detach will not
       complete until all buffered messages are delivered.)

ERRORS

       Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
       tions  do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before the error value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job, except  for
       I/O  function  errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be
       used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.

SEE ALSO

       MPI_Buffer_attach
       MPI_Ibsend
       MPI_Bsend_init

Open MPI 1.2							  September 2006					       MPI_Bsend(3OpenMPI)