NAME¶
MPI_Register_datarep - Defines data representation.
SYNTAX¶
C Syntax
#include <mpi.h>
int MPI_Register_datarep(char *datarep,
MPI_Datarep_conversion_function *read_conversion_fn,
MPI_Datarep_conversion_function *write_conversion_fn,
MPI_Datarep_extent_function *dtype_file_extent_fn,
void *extra_state)
Fortran Syntax¶
INCLUDE 'mpif.h'
MPI_REGISTER_DATAREP( DATAREP, READ_CONVERSION_FN,
WRITE_CONVERSION_FN, DTYPE_FILE_EXTENT_FN,
EXTRA_STATE, IERROR)
CHARACTER*(*) DATAREP
EXTERNAL READ_CONVERSION_FN, WRITE_CONVERSION_FN,
DTYPE_FILE_EXTENT_FN
INTEGER IERROR
INTEGER(KIND=MPI_ADDRESS_KIND) EXTRA_STATE
C++ Syntax¶
#include <mpi.h>
void MPI::Register_datarep(const char* datarep,
MPI::Datarep_conversion_function* read_conversion_fn,
MPI::Datarep_conversion_function* write_conversion_fn,
MPI::Datarep_extent_function* dtype_file_extent_fn,
void* extra_state)
- datarep
- Data representation identifier (string).
- read_conversion_fn
- Function invoked to convert from file representation to
native representation (function).
- write_conversion_fn
- Function invoked to convert from native representation to
file representation (function).
- dtype_file_extent_fn
- Function invoked to get the extent of a data type as
represented in the file (function).
- extra_state
- Extra state.
OUTPUT PARAMETER¶
- IERROR
- Fortran only: Error status (integer).
DESCRIPTION¶
MPI_Register_datarep defines a data representation. It associates the data
representation's identifier (a string) with the functions that convert from
file representation to the native representation and vice versa, with the
function that gets the extent of a data type as represented in the file, as
well as with "extra state," which is used for passing arguments.
Once a data representation has been registered using this routine, you may
specify its identifier as an argument to MPI_File_set_view, causing subsequent
data-access operations to call the specified conversion functions.
The call associates
read_conversion_fn,
write_conversion_fn, and
dtype_file_extent_fn with the data representation identifier
datarep.
datarep can then be used as an argument to
MPI_File_set_view, causing subsequent data access operations to call the
conversion functions to convert all data items accessed between file data
representation and native representation. MPI_Register_datarep is a local
operation and only registers the data representation for the calling MPI
process. If
datarep is already defined, an error in the error class
MPI_ERR_DUP_DATAREP is raised using the default file error handler. The length
of a data representation string is limited to the value of
MPI_MAX_DATAREP_STRING. MPI_MAX_DATAREP_STRING must have a value of at least
64. No routines are provided to delete data representations and free the
associated resources; it is not expected that an application will generate
them in significant numbers.
NOTES¶
The Fortran version of each MPI I/O routine includes a final argument, IERROR,
which is not defined in the PARAMETERS sections. This argument is used to
return the error status of the routine in the manner typical for Fortran
library routines.
The C version of each routine returns an error status as an integer return
value.
Error classes are found in mpi.h (for C), mpif.h (for Fortran), and mpi++.h (for
C++).
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. For
MPI I/O function errors, the default error handler is set to
MPI_ERRORS_RETURN. The error handler may be changed with
MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may
be used to make I/O errors fatal. Note that MPI does not guarantee that an MPI
program can continue past an error.