NAME¶

MPI_Type_create_keyval - Generates a new attribute key for caching on data types.

SYNTAX¶

C Syntax¶

#include <mpi.h>
int MPI_Type_create_keyval(MPI_Type_copy_attr_function * type_copy_attr_fn, 
	MPI_Type_delete_attr_function * type_delete_attr_fn, 
	int * type_keyval, void *extra_state)

Fortran Syntax (see FORTRAN 77 NOTES)¶

INCLUDE 'mpif.h'
MPI_TYPE_CREATE_KEYVAL( TYPE_COPY_ATTR_FN, TYPE_DELETE_ATTR_FN, 
		TYPE_KEYVAL, EXTRA_STATE, IERROR)
	EXTERNAL  TYPE_COPY_ATTR_FN, TYPE_DELETE_ATTR_FN
	INTEGER	 TYPE_KEYVAL, IERROR 
	INTEGER(KIND=MPI_ADDRESS_KIND)  EXTRA_STATE

C++ Syntax¶

#include <mpi.h>
static int MPI::Datatype::Create_keyval(MPI::Datatype::Copy_attr_function*
	 type_copy_attr_fn, MPI::Datatype::Delete_attr_function*
	 type_delete_attr_fn, void* extra_state)

INPUT PARAMETERS¶

type_copy_attr_fn

Copy callback function for type_keyval (function).

type_delete_attr_fn

Delete callback function for type_keyval (function).

extra_state

Extra state for callback functions.

 

OUTPUT PARAMETERS¶

type_keyval

Key value for future access (integer).

IERROR

Fortran only: Error status (integer).

 

DESCRIPTION¶

MPI_Type_create_keyval generates a new attribute key for caching on data types. This routine partially replaces MPI_Keyval_create. The argument type_copy_attr_fn may be specified as MPI_TYPE_NULL_COPY_FN or MPI_TYPE_DUP_FN from C, C++, or Fortran. MPI_TYPE_NULL_COPY_FN is a function that does nothing other than returning flag = 0 and MPI_SUCCESS. MPI_TYPE_DUP_FN is a simple-minded copy function that sets flag = 1, returns the value of attribute_val_in in attribute_val_out, and returns MPI_SUCCESS. The argument type_delete_attr_fn may be specified as MPI_TYPE_NULL_DELETE_FN from C, C++, or Fortran. MPI_TYPE_NULL_DELETE_FN is a function that does nothing beyond returning MPI_SUCCESS. The C callback functions are:

typedef int MPI_Type_copy_attr_function(MPI_Datatype  oldtype, 
            int  type_keyval, void *extra_state, void *attribute_val_in, 
            void * attribute_val_out, int *flag); 

and

typedef int MPI_Type_delete_attr_function(MPI_Datatype  type, int type_keyval, 
             void * attribute_val, void *extra_state); 

The Fortran callback functions are:

SUBROUTINE TYPE_COPY_ATTR_FN( OLDTYPE, TYPE_KEYVAL, EXTRA_STATE, 
             ATTRIBUTE_VAL_IN, ATTRIBUTE_VAL_OUT, FLAG, IERROR) 
    INTEGER  OLDTYPE, TYPE KEYVAL, IERROR
    INTEGER(KIND=MPI_ADDRESS_KIND)  EXTRA_STATE, 
        ATTRIBUTE_VAL_IN, ATTRIBUTE_VAL_OUT 
    LOGICAL  FLAG 

and

SUBROUTINE TYPE_DELETE_ATTR_FN( TYPE, TYPE_KEYVAL, ATTRIBUTE_VAL, EXTRA_STATE, 
             IERROR) 
    INTEGER  TYPE, TYPE_KEYVAL, IERROR 
    INTEGER(KIND=MPI_ADDRESS_KIND)  ATTRIBUTE VAL, EXTRA_STATE 

The C++ callbacks are:

typedef int MPI::Datatype::Copy_attr_function(const MPI::Datatype&  oldtype, 
             int  type_keyval, void* extra_state, 
             const void*  attribute_val_in, void* attribute_val_out, 
             bool&  flag); 

and

typedef int MPI::Datatype::Delete_attr_function(MPI::Datatype&  type, 
             int  type_keyval, void* attribute_val, void* extra_state); 

FORTRAN 77 NOTES¶

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

     INTEGER*MPI_ADDRESS_KIND  EXTRA_STATE

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_free_keyval