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MPI_Type_match_size(3) man page (version 1.8.1)

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Table of Contents

Name

MPI_Type_match_size - Returns an MPI datatype of a given type and

size

Syntax

C Syntax


#include <mpi.h>
int MPI_Type_match_size(int typeclass, int size,
    MPI_Datatype *type)

Fortran Syntax


INCLUDE ’mpif.h’
MPI_TYPE_MATCH_SIZE(TYPECLASS, SIZE, TYPE, IERROR)
    INTEGER    TYPECLASS, SIZE, TYPE, IERROR

C++ Syntax


#include <mpi.h>
static MPI::Datatype MPI::Match_size(int typeclass, int size)

Input Parameters

typeclass
Generic type specifier (integer).
size
Size, in bytes, of representation (integer).

Output Parameters

type
Datatype with correct type and size (handle).
IERROR
Fortran only: Error status (integer).

Description

The function returns an MPI datatype matching a local variable of type (typeclass, size). The returned type is a reference (handle) to a predefined named datatype, not a duplicate. This type cannot be freed.

The value of typeclass may be set to one of MPI_TYPECLASS_REAL, MPI_TYPECLASS_INTEGER, or MPI_TYPECLASS_COMPLEX, corresponding to the desired datatype.

MPI_type_match_size can be used to obtain a size-specific type that matches a Fortran numeric intrinsic type: first call MPI_Sizeof to compute the variable size, then call MPI_Type_match_size to find a suitable datatype. In C and C++, use the sizeof builtin instead of MPI_Sizeof.

It is erroneous to specify a size not supported by the compiler.

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 the MPI man page for a full list of MPI error codes.

See Also


MPI_Sizeof
MPI_Type_get_extent

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