Variable type equivalent to Variant(Optional) when using COM objects in MATLAB

I am using COM objects instantiated through activexserver.

One of the methods I am trying to use has the following input argument types specification (I got it using "methodsview" function)

ReadFile = void ReadFile(handle, ustring, Variant(Optional))

The COM object in fact has an optional in the second argument, with default value NULL ([in, defaultvalue(NULL)] )

What equivalent MATLAB type can I use for the Variant(Optional) type? I have tried no providing a second argument, using empty ([]), 0.

Thanks in advance!

Answer 1

[Spruha]

Hi Isaac,

I see you are working with a COM object and looking for a way to pass an optional second argument with a default value of NULL. In MATLAB, you can use the ‘variant([])’ function for this purpose. By passing an empty array ([]) of type double, MATLAB creates a VARIANT of type VT_EMPTY, which is commonly used to represent "no value" or NULL in COM interfaces.

Please refer to this documentation on handling COM data in MATLAB: https://www.mathworks.com/help/matlab/matlab_external/handling-com-data-in-matlab-software.html#bq4sbxq-1

Hope this helps!