MPI_Buffer_detach

 Removes an existing buffer (for use in MPI_Bsend etc)

Synopsis


#include "mpi.h"
int MPI_Buffer_detach( bufferptr, size )
void *bufferptr;
int  *size;

Output Parameters

buffer - initial buffer address (choice)
size - buffer size, in bytes (integer)

Notes

The reason that MPI_Buffer_detach returns the address and size of the buffer being detached is to allow nested libraries to replace and restore the buffer. For example, consider 


    int size, mysize, idummy;
    void *ptr, *myptr, *dummy;     
    MPI_Buffer_detach( &ptr, &size );
    MPI_Buffer_attach( myptr, mysize );
    ...
    ... library code ...
    ...
    MPI_Buffer_detach( &dummy, &idummy );
    MPI_Buffer_attach( ptr, size );

This is much like the action of the Unix signal routine and has the same strengths (it is simple) and weaknesses (it only works for nested usages).

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.

The Fortran binding for this routine is different. Because Fortran does not have pointers, it is impossible to provide a way to use the output of this routine to exchange buffers. In this case, only the size field is set.

Notes for C

Even though the bufferptr argument is declared as void *, it is really the address of a void pointer. See the rationale in the standard for more details.

Location:buffree.c