MPI_Type_get_contents(3)           Open MPI           MPI_Type_get_contents(3)



NAME
       MPI_Type_get_contents - Returns information about arguments used in
       creation of a data type.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Type_get_contents(MPI_Datatype datatype, int max_integers,
            int max_addresses, int max_datatypes, int array_of_integers[], MPI_Aint array_of_addresses[], MPI_Datatype array_of_datatypes[])


Fortran Syntax (see FORTRAN 77 NOTES)
       INCLUDE 'mpif.h'
       MPI_TYPE_GET_CONTENTS(DATATYPE, MAX_INTEGERS, MAX_ADDRESSES,
                 MAX_DATATYPES, ARRAY_OF_INTEGERS, ARRAY_OF_ADDRESSES,
                 ARRAY_OF_DATATYPES, IERROR)
            INTEGER   DATATYPE, MAX_INTEGERS, MAX_ADDRESSES, MAX_DATATYPES
            INTEGER   ARRAY_OF_INTEGERS(*), ARRAY_OF_DATATYPES(*), IERROR
            INTEGER(KIND=MPI_ADDRESS_KIND) ARRAY_OF_ADDRESSES(*)


C++ Syntax
       #include <mpi.h>
       void MPI::Datatype::Get_contents(int max_integers, int max_addresses,
            int max_datatypes, int array_of_integers[],
            MPI::Aint array_of_addresses[],
            MPI::Datatype array_of_datatypes[]) const


INPUT PARAMETERS
       datatype  Data type to access (handle).

       max_integers
                 Number of elements in array_of_integers (nonnegative
                 integer).

       max_addresses
                 Number of elements in array_of_addresses (nonnegative
                 integer).

       max_datatypes
                 Number of elements in array_of_datatypes (nonnegative
                 integer).


OUTPUT PARAMETERS
       array_of_integers
                 Contains integer arguments used in constructing datatype
                 (array of integers).

       array_of_addresses
                 Contains address arguments used in constructing datatype
                 (array of integers).

       array_of_datatypes
                 Contains data-type arguments used in constructing datatype
                 (array of integers).

       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 the 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.

       The parameter datatype must be a predefined unnamed or a derived data
       type. The call is erroneous if datatype is a predefined named data
       type.

       The values given for max_integers, max_addresses, and max_datatypes
       must be at least as large as the value returned in num_integers,
       num_addresses, and num_datatypes, respectively, in the call
       MPI_Type_get_envelope for the same datatype argument.

       The data types returned in array_of_datatypes are handles to data-type
       objects that are equivalent to the data types used in the original
       construction call. If these were derived data types, then the returned
       data types are new data-type objects, and the user is responsible for
       freeing these datatypes with MPI_Type_free. If these were predefined
       data types, then the returned data type is equal to that (constant)
       predefined data type and cannot be freed.

       The committed state of returned derived data types is undefined, that
       is, the data types may or may not be committed. Furthermore, the
       content of attributes of returned data types is undefined.

       Note that MPI_Type_get_contents can be invoked with a data-type
       argument that was constructed using MPI_Type_create_f90_real,
       MPI_Type_create_f90_integer, or MPI_Type_create_f90_complex (an unnamed
       predefined data type). In such a case, an empty array_of_datatypes is
       returned.

       In the MPI-1 data-type constructor calls, the address arguments in
       Fortran are of type INTEGER. In the new MPI-2 calls, the address
       arguments are of type INTEGER(KIND=MPI ADDRESS KIND). The call
       MPI_Type_get_contents returns all addresses in an argument of type
       INTEGER(KIND=MPI ADDRESS KIND). This is true even if the old MPI-1
       calls were used. Thus, the location of values returned can be thought
       of as being returned by the C bindings. It can also be determined by
       examining the new MPI-2 calls for data-type constructors for the
       deprecated MPI-1 calls that involve addresses.


FORTRAN 77 NOTES
       The MPI standard prescribes portable Fortran syntax for the
       ARRAY_OF_ADDRESSES argument only for Fortran 90. FORTRAN 77 users may
       use the non-portable syntax

            INTEGER*MPI_ADDRESS_KIND ARRAY_OF_ADDRESSES(*)

       where MPI_ADDRESS_KIND is a constant defined in mpif.h and gives the
       length of the declared integer in bytes.


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_envelope




1.4.1                            Jan 14, 2010         MPI_Type_get_contents(3)
