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MPI_Bsend(3)			      MPI			  MPI_Bsend(3)

NAME
       MPI_Bsend -  Basic send with user-provided buffering

SYNOPSIS
       int MPI_Bsend(MPICH2_CONST void *buf, int count,	MPI_Datatype datatype, int dest, int tag,
		     MPI_Comm comm)

INPUT PARAMETERS
       buf    -	initial	address	of send	buffer (choice)
       count  -	number of elements 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)

NOTES
       This  send is provided as a convenience function; it allows the user to
       send messages without worring 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_Bsend	s  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.)

THREAD AND INTERRUPT SAFETY
       This routine is thread-safe.  This  means  that	this  routine  may  be
       safely  used by multiple	threads	without	the need for any user-provided
       thread locks.  However, the routine is not interrupt safe.   Typically,
       this  is	due to the use of memory allocation routines such as malloc or
       other non-MPICH runtime routines	that  are  themselves  not  interrupt-
       safe.

NOTES FOR FORTRAN
       All  MPI	routines in Fortran (except for	MPI_WTIME and MPI_WTICK	) have
       an additional argument ierr at the end of the argument list.   ierr  is
       an  integer and has the same meaning as the return value	of the routine
       in C.  In Fortran, MPI routines are subroutines,	and are	 invoked  with
       the call	statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm )	are of type INTEGER in
       Fortran.

ERRORS
       All MPI routines	(except	MPI_Wtime and  MPI_Wtick  )  return  an	 error
       value;  C routines as the value of the function and Fortran routines in
       the last	argument.  Before the value is returned, the current MPI error
       handler	is called.  By default,	this error handler aborts the MPI job.
       The error handler may be	changed	with MPI_Comm_set_errhandler (for com-
       municators),  MPI_File_set_errhandler  (for files), and MPI_Win_set_er-
       rhandler	(for RMA windows).  The	MPI-1 routine  MPI_Errhandler_set  may
       be  used	 but  its  use	is  deprecated.	  The predefined error handler
       MPI_ERRORS_RETURN may be	used to	cause error  values  to	 be  returned.
       Note  that MPI does not guarentee that an MPI program can continue past
       an error; however, MPI implementations will attempt to  continue	 when-
       ever possible.

       MPI_SUCCESS
	      -	No error; MPI routine completed	successfully.
       MPI_ERR_COMM
	      -	 Invalid communicator.	A common error is to use a null	commu-
	      nicator 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_RANK
	      -	Invalid	source or destination rank.   Ranks  must  be  between
	      zero  and	the size of the	communicator minus one;	ranks in a re-
	      ceive ( MPI_Recv , MPI_Irecv , MPI_Sendrecv , etc.) may also  be
	      MPI_ANY_SOURCE .

       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 .

SEE ALSO
       MPI_Buffer_attach, MPI_Ibsend, MPI_Bsend_init

LOCATION
       src/mpi/pt2pt/bsend.c

				   9/20/2012			  MPI_Bsend(3)

NAME | SYNOPSIS | INPUT PARAMETERS | NOTES | THREAD AND INTERRUPT SAFETY | NOTES FOR FORTRAN | ERRORS | SEE ALSO | LOCATION

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