External Interfaces

Converting Data

Since COM defines a number of different data formats and types, you need to know how MATLAB converts data from COM objects into variables in the MATLAB workspace. Data from COM objects must be converted:

• When a property value is retrieved
• When a value is returned from a method invocation

This chart shows how COM data types are converted into variables in the MATLAB workspace.

Passing Data from MATLAB to ActiveX Objects.

The following table shows the mapping of MATLAB data types to COM data types that you must use to pass data from MATLAB to an ActiveX object.

Note that all other types result in a warning:

"ActiveX -- invalid argument type or value".

MATLAB Data Type	Converted to COM Data Type
double	VT_R8 (8 byte real)
NaN	VT_ERROR (SCODE)
CHAR	VT_BSTR (OLE Automation string)
SINGLE	VT_R4 (4 byte real)
INT8	VT_I1 (signed char)
UINT8	VT_UI1 (unsigned char)
INT16	VT_I2 (2 byte signed int)
UINT16	VT_UI2 (unsigned short)
INT32	VT_I4 (4 byte signed int)
UINT32	VT_UI4 (unsigned long)
INT64	VT_I8 (signed 64-bit int)
UINT64	VT_UI8 (unsigned 64-bit int)
Cell Array	VT_SAFEARRAY(VARIANT) (use VT_ARRAY in VARIANT)
Logical	VT_BOOL (VARIANT_BOOL) True=-1, False=0
Handle	VT_DISPATCH (IDispatch *)

Additional COM Client Information

Using MATLAB as a DCOM Client

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