MPI_Pack_size(3) Open MPI MPI_Pack_size(3)NAMEMPI_Pack_size - Returns the upper bound on the amount of space needed
to pack a message.
SYNTAXC Syntax
#include <mpi.h>
int MPI_Pack_size(int incount, MPI_Datatype datatype, MPI_Comm comm,
int *size)
Fortran Syntax
INCLUDE 'mpif.h'
MPI_PACK_SIZE(INCOUNT, DATATYPE, COMM, SIZE, IERROR)
INTEGER INCOUNT, DATATYPE, COMM, SIZE, IERROR
C++ Syntax
#include <mpi.h>
int Datatype::Pack_size(int incount, const Comm& comm) const
INPUT PARAMETERS
incount Count argument to packing call (integer).
datatype Datatype argument to packing call (handle).
comm Communicator argument to packing call (handle).
OUTPUT PARAMETERS
size Upper bound on size of packed message, in bytes (integer).
IERROR Fortran only: Error status (integer).
DESCRIPTIONMPI_Pack_size allows the application to find out how much space is
needed to pack a message. A call to MPI_Pack_size(incount, datatype,
comm, size) returns in size an upper bound on the increment in position
that would occur in a call to MPI_Pack, with the same values for
incount, datatype, and comm.
Rationale: The call returns an upper bound, rather than an exact
bound, since the exact amount of space needed to pack the message may
depend on the context (e.g., first message packed in a packing unit may
take more space).
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 ALSO
MPI_Pack
MPI_Unpack
1.7.4 Feb 04, 2014 MPI_Pack_size(3)
