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MPI_Pack_external_size(3OpenMPI)              MPI_Pack_external_size(3OpenMPI)




NAME

       MPI_Pack_external_size  -  Calculates  upper  bound  on space needed to
       write to a portable format



SYNTAX


C Syntax

       #include <mpi.h>
       int MPI_Pack_external_size(char *datarep, int incount,
            MPI_Datatype datatype, MPI_Aint *size)



Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_PACK_EXTERNAL_SIZE(DATAREP, INCOUNT, DATATYPE, SIZE, IERROR)

            INTEGER        INCOUNT, DATATYPE, IERROR
            INTEGER (KIND=MPI_ADDRESS_KIND) SIZE
            CHARACTER*(*)  DATAREP



C++ Syntax

       #include <mpi.h>
       MPI::Aint MPI::Datatype::Pack_external_size(const char* datarep,
            int incount) const



INPUT PARAMETERS

       datarep   Data representation (string).

       incount   Number of input data items (integer).

       datatype  Datatype of each input data item (handle).



OUTPUT PARAMETERS

       size      Upper bound on size of packed message, in bytes (integer).

       IERROR    Fortran only: Error status (integer).



DESCRIPTION

       MPI_Pack_external_size allows the application  to  find  out  how  much
       space is needed to pack a message in the portable format defined by the
       MPI Forum. It returns in size an upper bound on the increment in  posi-
       tion that would occur in a call to MPI_Pack_external with the same val-
       ues for datarep, incount, and datatype.

       The call returns an upper bound, rather than an  exact  bound,  as  the
       exact  amount of space needed to pack the message may depend on context
       and alignment (e.g., the first message packed in  a  packing  unit  may
       take more space).



NOTES

       The datarep argument specifies the data format. The only valid value in
       the current version of MPI is "external32". The  argument  is  provided
       for future extensibility.



ERRORS

       Almost  all MPI routines return an error value; C routines as the value
       of the function and Fortran routines in the last  argument.  C++  func-
       tions  do  not  return  errors.  If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before  the  error  value is returned, the current MPI error handler is
       called. By default, this error handler aborts the MPI job,  except  for
       I/O   function   errors.   The   error  handler  may  be  changed  with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN
       may  be  used  to cause error values to be returned. Note that MPI does
       not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.



SEE ALSO

       MPI_Pack_external(3), MPI_Unpack_external(3)




Open MPI 1.2                    September 2006MPI_Pack_external_size(3OpenMPI)

Mac OS X 10.6 - Generated Thu Sep 17 20:13:12 CDT 2009
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