plucky (3) MPI_Type_get_contents.openmpi.3.gz

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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,  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
       :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  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 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  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
       Almost  all  MPI  routines  return  an  error  value; C routines as the return result of the function and
       Fortran routines in the last argument.

       Before the error value is returned, the current MPI  error  handler  associated  with  the  communication
       object  (e.g.,  communicator, window, file) is called.  If no communication object is associated with the
       MPI call, then the call is considered attached to MPI_COMM_SELF and will call the  associated  MPI  error
       handler.   When   MPI_COMM_SELF   is   not  initialized  (i.e.,  before  MPI_Init/MPI_Init_thread,  after
       MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial  error  handler.
       The  initial  error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using
       the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info  key  to  MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.   If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN
       error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is  called  for  all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called on a communicator, it acts as if MPI_Abort was called on  that  communicator.  If  called  on  a
         window  or file, acts as if MPI_Abort was called on a communicator containing the group of processes in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

       SEE ALSO:

          • MPI_Type_get_envelope


       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                          MPI_TYPE_GET_CONTENTS(3)