Skip to content

Latest commit

 

History

History
131 lines (97 loc) · 4.81 KB

MPI_Type_get_contents.3.rst

File metadata and controls

131 lines (97 loc) · 4.81 KB
Raw

MPI_Type_get_contents

:ref:`MPI_Type_get_contents` |mdash| 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

USE MPI
! or the older form: 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(*)

Fortran 2008 Syntax

USE mpi_f08
MPI_Type_get_contents(datatype, max_integers, max_addresses, max_datatypes,
     array_of_integers, array_of_addresses, array_of_datatypes,
             ierror)
     TYPE(MPI_Datatype), INTENT(IN) :: datatype
     INTEGER, INTENT(IN) :: max_integers, max_addresses, max_datatypes
     INTEGER, INTENT(OUT) :: array_of_integers(max_integers)
     INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(OUT) ::
     array_of_addresses(max_addresses)
     TYPE(MPI_Datatype), INTENT(OUT) :: array_of_datatypes(max_datatypes)
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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

In the legacy MPI-1 datatype constructor calls, the address arguments in Fortran are of type INTEGER. In subsequent versions of the MPI Standard, the address arguments are of type INTEGER(KIND=MPI_ADDRESS_KIND). The call :ref:`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 current MPI calls for datatype constructors for the deprecated MPI-1 calls that involve addresses.

ERRORS

.. seealso::
   * :ref:`MPI_Type_get_envelope`