NAME

       MPI_Buffer_attach -  Attaches a user-defined buffer for sending

SYNOPSIS

       #include <mpi.h>
       int MPI_Buffer_attach(void *buf, int size)

INPUT PARAMETERS

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

NOTES

       The size given should be the sum of the sizes of all outstanding Bsends that you intend to
       have, plus a few hundred  bytes  for  each  Bsend  that  you  do.   For  the  purposes  of
       calculating size, you should use MPI_Pack_size .  In other words, in the code

       MPI_Buffer_attach( buffer, size );
       MPI_Bsend( ..., count=20, datatype=type1,  ... );
       .
       .
       .
       MPI_Bsend( ..., count=40, datatype=type2, ... );

       the  value of size in the MPI_Buffer_attach call should be greater than the value computed
       by

       MPI_Pack_size(20, type1, comm, &s1);
       MPI_Pack_size(40, type2, comm, &s2);
       size = s1 + s2 + 2 * MPI_BSEND_OVERHEAD;

       MPI_Bsend_overhead gives the maximum amount of space that may be used in  the  buffer  for
       use  by the Bsend routines in using the buffer.  This value is in mpi.h (for C) and mpif.h
       (for Fortran).

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

       If  an  error occurs in an MPI function, the current MPI error handler is called to handle
       it.  By default, this error handler aborts the MPI job.  The error handler may be  changed
       with  MPI_Errhandler_set  ;  the predefined error handler MPI_ERRORS_RETURN may be used to
       cause error values to be returned (in C and Fortran; this error handler is less useful  in
       with  the  C++  MPI  bindings.   The predefined error handler MPI::ERRORS_THROW_EXCEPTIONS
       should be used in C++ if the error value needs to be recovered).  Note that MPI  does  not
       guarantee that an MPI program can continue past an error.

       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.  The C++ bindings for
       MPI  do  not  return  error  values;  instead,  error  values are communicated by throwing
       exceptions of type MPI::Exception (but not by default).  Exceptions are only thrown if the
       error value is not MPI::SUCCESS .

       Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return
       upon an error, there will be no way to recover what the actual error value was.
       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_BUFFER
              - Invalid buffer pointer.  Usually a null buffer where one is not valid.
       MPI_ERR_INTERN
              - An internal error has been detected.  This is fatal.  Please send a bug report to
              the LAM mailing list (see http://www.lam-mpi.org/contact.php ).

SEE ALSO

       MPI_Buffer_detach, MPI_Bsend

MORE INFORMATION

       For  more information, please see the official MPI Forum web site, which contains the text
       of both the MPI-1 and MPI-2 standards.  These documents contain detailed information about
       each MPI function (most of which is not duplicated in these man pages).

       http://www.mpi-forum.org/

ACKNOWLEDGEMENTS

       The  LAM  Team  would  like the thank the MPICH Team for the handy program to generate man
       pages  ("doctext"  from  ftp://ftp.mcs.anl.gov/pub/sowing/sowing.tar.gz  ),  the   initial
       formatting, and some initial text for most of the MPI-1 man pages.

LOCATION

       bufattach.c