MPI_Register_datarep(3) Open MPI MPI_Register_datarep(3)
NAME
MPI_Register_datarep - Defines data representation.
SYNTAX
C Syntax
#include <mpi.h>
int 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)
Fortran Syntax
USE MPI
! or the older form: 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
Fortran 2008 Syntax
USE mpi_f08
MPI_Register_datarep(datarep, read_conversion_fn, write_conversion_fn,
dtype_file_extent_fn, extra_state, ierror)
CHARACTER(LEN=*), INTENT(IN) :: datarep
PROCEDURE(MPI_Datarep_conversion_function) :: read_conversion_fn
PROCEDURE(MPI_Datarep_conversion_function) :: write_conversion_fn
PROCEDURE(MPI_Datarep_extent_function) :: dtype_file_extent_fn
INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: extra_state
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
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)
INPUT PARAMETERS
datarep Data representation identifier (string).
read_conversion_fn
Function invoked to convert from file representation to na-
tive 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 repre-
sented 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 repre-
sented 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 re-
turn 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++ func-
tions 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_ER-
RORS_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.
4.1.2 Nov 24, 2021 MPI_Register_datarep(3)
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