Manpages - MPI_Type_get_envelope.3

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

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

  USE MPI
  ! or the older form: 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

  USE mpi_f08
  MPI_Type_get_envelope(datatype, num_integers, num_addresses, num_datatypes,
  		combiner, ierror)
  	TYPE(MPI_Datatype), INTENT(IN) :: datatype
  	INTEGER, INTENT(OUT) :: num_integers, num_addresses, num_datatypes,
  	combiner
  	INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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

datatype

Data type to access (handle).

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).

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.

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            MPI_Type_hvector
  MPI_COMBINER_INDEXED            MPI_Type_indexed
  MPI_COMBINER_HINDEXED           MPI_Type_hindexed
  MPI_COMBINER_INDEXED_BLOCK      MPI_Type_create_indexed_block
  MPI_COMBINER_STRUCT             MPI_Type_struct
  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.

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_Type_get_contents