Producing a COM Class
Producing a COM class requires the generation of
A class definition file in Interface Description Language (IDL)
One or more associated C++ class definition/implementation files
The MATLAB® Compiler SDK™ product automatically produces the necessary IDL and C/C++ code to build each COM class in the component. This process is generally transparent to you when you use the compiler to generate a COM component, and to users of the COM component when they program with it.
For information about IDL and C++ coding rules for building COM objects and for mappings to other languages, see articles in the MSDN Library.
The following table shows the mapping of a generic MATLAB function to IDL code and to Microsoft® Visual Basic®.
|Generic MATLAB Code||
function [Y1, Y2, ..., varargout] = foo(X1, X2, ..., varargin)
HRESULT foo([in] long nargout, [in,out] VARIANT* Y1, [in,out] VARIANT* Y2, . . [in,out] VARIANT* varargout, [in] VARIANT X1, [in] VARIANT X2, . . [in] VARIANT varargin);
|Visual Basic Code||
Sub foo(nargout As Long, _ Y1 As Variant, _ Y2 As Variant, _ . . varargout As Variant, _ X1 As Variant, _ X2 As Variant, _ . . varargin As Variant)
The IDL function definition is generated by producing a function with
the same name as the original MATLAB function and an argument list containing all inputs
and outputs of the original plus one additional parameter,
When present, the
nargout parameter is an
[in] parameter of type
long. It is always the first argument in
the list. This parameter allows correct passage of the MATLAB
nargout parameter to the compiled MATLAB code. The
nargout parameter is not
produced if you encapsulate a MATLAB function containing no outputs.
nargout parameter, the outputs are
listed in the order they appear on the left side of the MATLAB function, and are tagged as
[in,out], meaning that they are passed in
The function inputs are listed next, appearing in the same order as
they do on the right side of the original function. All inputs are
When present, the optional
parameters are always listed as the last input parameters and the
last output parameters. All parameters other than
nargout are passed as COM
VARIANT types. For a list of rules for
conversion between MATLAB arrays and COM
VARIANTs, see Data Conversion.
Microsoft Visual Basic Mapping
Visual Basic provides native support for COM
Variants with the
Variant type, as well as implicit
conversions for all Visual Basic primitive types to and from
Variants. In general, arrays/scalars of any
Visual Basic primitive type, as well as arrays/scalars of Variant
types, can be passed as arguments.
Compiler SDK COM components also provide direct support for the
Range object, used by Visual Basic for Applications to represent a range of cells in an
See the Visual Basic for Applications documentation included with Microsoft Excel for more information on Visual Basic data types.
See the MSDN
Library for more information about Visual Basic and about Excel