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MPI_Pack_size - Returns the upper bound on the amount of space
needed to pack a message.
#include <mpi.h>
int MPI_Pack_size(int incount, MPI_Datatype datatype, MPI_Comm comm,
int *size)
USE MPI
! or the older form: INCLUDE ’mpif.h’
MPI_PACK_SIZE(INCOUNT, DATATYPE, COMM, SIZE, IERROR)
INTEGER INCOUNT, DATATYPE, COMM, SIZE, IERROR
USE mpi_f08
MPI_Pack_size(incount, datatype, comm, size, ierror)
INTEGER, INTENT(IN) :: incount
TYPE(MPI_Datatype), INTENT(IN) :: datatype
TYPE(MPI_Comm), INTENT(IN) :: comm
INTEGER, INTENT(OUT) :: size
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
- incount
- Count argument to packing call (integer).
- datatype
- Datatype argument to packing call (handle).
- comm
- Communicator argument to
packing call (handle).
- size
- Upper bound on size of packed
message, in bytes (integer).
- IERROR
- Fortran only: Error status (integer).
MPI_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).
Almost all MPI routines return an error
value; C routines as the value of the function and Fortran routines in
the last argument. C++ functions 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.
MPI_Pack
MPI_Unpack
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