MPI_BUFFER_ATTACH(3)MPI_BUFFER_ATTACH(3)NAMEMPI_Buffer_attach - Attaches a user-defined buffer for sending
SYNOPSIS
C:
#include <mpi.h>
int MPI_Buffer_attach( buffer, size )
void *buffer;
int size;
C++:
#include <mpi.h>
void Attach_buffer(
void* buffer,
int size)
Fortran:
INCLUDE "mpif.h" (or USE MPI)
<type> BUFFER(*)
INTEGER size, ierror
CALL MPI_BUFFER_ATTACH(buffer, size, ierror)
STANDARDS
This release implements the MPI 1.2 standard, as documented by the MPI
Forum in the spring 1997 release of MPI: A Message Passing Interface
Standard.
DESCRIPTION
The MPI_Buffer_attach routine attaches a user-defined buffer for send
operations. This routine accepts the following parameters:
buffer Specifies the initial buffer address (choice)
size Specifies the buffer size, in bytes (integer)
ierror Specifies the return code value for successful completion,
which is in MPI_SUCCESS. MPI_SUCCESS is defined in the mpif.h
file.
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MPI_BUFFER_ATTACH(3)MPI_BUFFER_ATTACH(3)NOTES
The specified size should be the sum of the sizes of all outstanding
MPI_Bsend(3) operations that you intend to have, plus a few hundred bytes
for each MPI_Bsend(3) operation that you perform. For the purposes of
calculating size, you should use the MPI_Pack_size(3) routine for size
accuracy. In other words, in the following code samples, the value of
size in the MPI_Buffer_attach call should be greater than the value of
size computed by MPI_Pack_size.
MPI_Buffer_attach( buffer, size );
MPI_Bsend(, count=20, datatype=type1, );
MPI_Bsend(, count=40, datatype=type2, );
MPI_Pack_size( 20, type1, comm, &s1 );
MPI_Pack_size( 40, type2, comm, &s2 );
size = s1 + s2 + 2 * MPI_BSEND_OVERHEAD;
MPI_BSEND_OVERHEAD is the maximum amount of buffer space allocated for
use by each MPI_Bsend(3) routine. This value is located in mpi.h (for C)
and in mpif.h (for Fortran).
SEE ALSOintro_streams(3), MPI_Bsend(3), MPI_Buffer_detach(3), MPI_Pack_size(3)
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