MPI_File_get_type_extent(3) MPI-2 MPI_File_get_type_extent(3)NAME
MPI_File_get_type_extent - Returns the extent of datatype in the file
SYNOPSIS
#include "mpi.h"
int MPI_File_get_type_extent(MPI_File fh, MPI_Datatype datatype,
MPI_Aint *extent)
INPUT PARAMETERS
fh - file handle (handle)
datatype
- datatype (handle)
OUTPUT PARAMETERS
extent - extent of the datatype (nonnegative integer)
NOTES FOR FORTRAN
All MPI routines in Fortran (except for 'MPI_WTIME' and 'MPI_WTICK') have an additional argument 'ierr' at the end of the argument list.
the routine in C. In Fortran, MPI routines are subroutines and are invoked with the 'call' statement.
All MPI objects (e.g., 'MPI_Datatype', 'MPI_Comm', 'MPI_File') are of type 'INTEGER' in Fortran.
2/5/1998 MPI_File_get_type_extent(3)
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MPI_File_get_type_extent(3OpenMPI)MPI_File_get_type_extent(3OpenMPI)NAME
MPI_File_get_type_extent - Returns the extent of the data type in a file.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_File_get_type_extent(MPI_File fh, MPI_Datatype
datatype, MPI_Aint *extent)
Fortran Syntax (see FORTRAN 77 NOTES)
INCLUDE 'mpif.h'
MPI_FILE_GET_TYPE_EXTENT(FH, DATATYPE, EXTENT, IERROR)
INTEGER FH, DATATYPE, IERROR
INTEGER(KIND=MPI_ADDRESS_KIND) EXTENT
C++ Syntax
#include <mpi.h>
MPI::Aint MPI::File::Get_type_extent(const MPI::Datatype&
datatype) const
INPUT PARAMETERS
fh File handle (handle).
datatype Data type (handle).
OUTPUT PARAMETERS
extent Data type extent (integer).
IERROR Fortran only: Error status (integer).
DESCRIPTION
MPI_File_get_type_extent can be used to calculate extent for datatype in the file. The extent is the same for all processes accessing the
file associated with fh. If the current view uses a user-defined data representation, MPI_File_get_type_extent uses the
dtype_file_extent_fn callback to calculate the extent.
FORTRAN 77 NOTES
The MPI standard prescribes portable Fortran syntax for the EXTENT argument only for Fortran 90. FORTRAN 77 users may use the non-portable
syntax
INTEGER*MPI_ADDRESS_KIND EXTENT
where MPI_ADDRESS_KIND is a constant defined in mpif.h and gives the length of the declared integer in bytes.
NOTES
If the file data representation is other than "native," care must be taken in constructing etypes and file types. Any of the data-type con-
structor functions may be used; however, for those functions that accept displacements in bytes, the displacements must be specified in
terms of their values in the file for the file data representation being used. MPI will interpret these byte displacements as is; no scal-
ing will be done. The function MPI_File_get_type_extent can be used to calculate the extents of data types in the file. For etypes and
file types that are portable data types, MPI will scale any displacements in the data types to match the file data representation. Data
types passed as arguments to read/write routines specify the data layout in memory; therefore, they must always be constructed using dis-
placements corresponding to displacements in memory.
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_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.
Open MPI 1.2 September 2006 MPI_File_get_type_extent(3OpenMPI)