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       MPI_Buffer_attach -  Attaches a user-defined buffer for sending


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


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


       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).


       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


       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.
              - No error; MPI routine completed successfully.
              -  Invalid  buffer  pointer.  Usually a null buffer where one is
              not valid.
              - An internal error has been detected.  This is  fatal.   Please
              send  a  bug report to the LAM mailing list (see http://www.lam-


       MPI_Buffer_detach, MPI_Bsend


       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).


       The  LAM Team would like the thank the MPICH Team for the handy program
       to       generate        man        pages        ("doctext"        from     ),    the    initial
       formatting, and some initial text for most of the MPI-1 man pages.