MPI_Type_get_envelope(3)           Open MPI           MPI_Type_get_envelope(3)



NAME
       MPI_Type_get_envelope - Returns informaion about input arguments
       associated with a data type.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Type_get_envelope(MPI_Datatype datatype, int *num_integers,
            int *num_addresses, int *num_datatypes, int *combiner)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_TYPE_GET_ENVELOPE(DATATYPE, NUM_INTEGERS, NUM_ADDRESSES,
                 NUM_DATATYPES, COMBINER, IERROR)
            INTEGER   DATATYPE, NUM_INTEGERS, NUM_ADDRESSES
            INTEGER   NUM_DATATYPES, COMBINER, IERROR


C++ Syntax
       #include <mpi.h>
       void MPI::Datatype::Get_envelope(int& num_integers,
            int& num_addresses, int& num_datatypes,
            int& combiner) const


INPUT PARAMETER
       datatype  Data type to access (handle).


OUTPUT PARAMETERS
       num_integers
                 Number of input integers used in the call constructing
                 combiner (nonnegative integer).

       num_addresses
                 Number of input addresses used in the call constructing
                 combiner (nonnegative integer).

       num_datatypes
                 Number of input data types used in the call constructing
                 combiner (nonnegative integer).

       combiner  Combiner (state).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       For the given data type, MPI_Type_get_envelope returns information on
       the number and type of input arguments used in teh call that created
       the data type. The number-of-arguments values returned can be used to
       provide sufficiently large arrays in the decoding routine
       MPI_Type_get_contents. This call and the meaning of the returned values
       is described below. The combiner reflects the MPI data type constructor
       call that was used in creating datatype.


NOTES
       These are the values that can be returned in combiner and their
       associated calls:

       Values                          Associated Calls

       MPI_COMBINER_NAMED              a named predefined data type
       MPI_COMBINER_DUP                MPI_Type_dup
       MPI_COMBINER_CONTIGUOUS         MPI_Type_contiguous
       MPI_COMBINER_VECTOR             MPI_Type_vector
       MPI_COMBINER_HVECTOR_INTEGER    MPI_Type_hvector from Fortran
       MPI_COMBINER_HVECTOR            MPI_Type_hvector from C or C++
                                         and MPI_Type_create for
                                         all languages
       MPI_COMBINER_INDEXED            MPI_Type_indexed
       MPI_COMBINER_HINDEXED_INTEGER   MPI_Type_hindexed from Fortran
       MPI_COMBINER_HINDEXED           MPI_Type_hindexed from C or C++
                                         and MPI_Type_create_hindexed
                                         for all languages
       MPI_COMBINER_INDEXED_BLOCK      MPI_Type_create_indexed_block
       MPI_COMBINER_STRUCT_INTEGER     MPI_Type_struct from Fortran
       MPI_COMBINER_STRUCT             MPI_Type_struct from C or C++
                                         and MPI_Type_create_struct
                                         for all languages
       MPI_COMBINER_SUBARRAY           MPI_Type_create_subarray
       MPI_COMBINER_DARRAY             MPI_Type_create_darray
       MPI_COMBINER_F90_REAL           MPI_Type_create_f90_real
       MPI_COMBINER_F90_COMPLEX        MPI_Type_create_f90_complex
       MPI_COMBINER_F90_INTEGER        MPI_Type_create_f90_integer
       MPI_COMBINER_RESIZED            MPI_Type_create_resized

       If combiner is MPI_COMBINER_NAMED, then datatype is a named predefined
       data type.

       The actual arguments used in the creation call for a data type can be
       obtained from the call MPI_Type_get_contents.


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++
       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.


SEE ALSO
       MPI_Type_get_contents




1.4.1                            Jan 14, 2010         MPI_Type_get_envelope(3)
