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MPI_Type_get_true_extent, MPI_Type_get_true_extent_x - Returns
the true lower bound and extent of a data type’s corresponding typemap,
ignoring MPI_UB and MPI_LB markers.
#include <mpi.h>
int MPI_Type_get_true_extent(MPI_Datatype datatype,
MPI_Aint *true_lb, MPI_Aint *true_extent)
int MPI_Type_get_true_extent_x(MPI_Datatype datatype,
MPI_Count *true_lb, MPI_Count *true_extent)
INCLUDE ’mpif.h’
MPI_TYPE_GET_TRUE_EXTENT(DATATYPE, TRUE_LB, TRUE_EXTENT, IERROR)
INTEGER DATATYPE, IERROR
INTEGER(KIND=MPI_ADDRESS_KIND) TRUE_LB, TRUE_EXTENT
MPI_TYPE_GET_TRUE_EXTENT_X(DATATYPE, TRUE_LB, TRUE_EXTENT, IERROR)
INTEGER DATATYPE, IERROR
INTEGER(KIND=MPI_COUNT_KIND) TRUE_LB, TRUE_EXTENT
#include <mpi.h>
void MPI::Datatype::Get_true_extent(MPI::Aint& true_lb,
MPI::Aint& true_extent) const
- datatype
- Data type for which information is wanted
(handle).
- true_lb
- True lower bound of data type (integer).
- true_extent
- True size of data type (integer).
- IERROR
- Fortran only: Error
status (integer).
The true_lb parameter returns the offset
of the lowest unit of store that is addressed by the data type, that is,
the lower bound of the corresponding typemap, ignoring MPI_LB markers. The
true_extent parameter returns the true size of the data type, that is,
the extent of the corresponding typemap, ignoring MPI_LB and MPI_UB markers,
and performing no rounding for alignment. For both functions, if either
the true_lb or true_extent parameter cannot express the value to be returned
(e.g., if the parameter is too small to hold the output value), it is set
to MPI_UNDEFINED.
The true_extent is the minimum number of bytes of memory
necessary to hold a data type, uncompressed.
See § 4.1.8 of the MPI-3 standard
for more detailed definitions of these parameters in relation to the typemap.
The MPI standard prescribes portable Fortran syntax for
the TRUE_LB and TRUE_EXTENT arguments only for Fortran 90. FORTRAN 77 users
may use the non-portable syntax
MPI_Type_get_true_extent:
INTEGER*MPI_ADDRESS_KIND TRUE_LB
or
INTEGER*MPI_ADDRESS_KIND TRUE_EXTENT
MPI_Type_get_true_extent_x:
INTEGER*MPI_COUNT_KIND TRUE_LB
or
INTEGER*MPI_COUNT_KIND TRUE_EXTENT
where MPI_ADDRESS_KIND and MPI_COUNT_KIND are constants defined in mpif.h
and give the length of the declared integer in bytes.
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.
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