MATLAB: Do I receive an error when trying to invoke a method on an object that has reference or optional arguments

activexargumentsinvokeMATLABmethodoptionalreference

Why do I receive an error when trying to invoke a method on an object that has reference or
optional arguments?
Consider a COM object that has a method with following signature:
 [id(1), helpstring("method AllinOne")] HRESULT AllinOne([in] double db, [out] BSTR* strout, 
 [in, out] long* ln, [in,optional] BSTR strin, [out, optional] VARIANT* var, 
 [out,retval] BOOL* bret);
This is the code I use in MATLAB:
h=actxserver('TestServer.ArgTest.1');
[a,b,c,d] = invoke(h, 'AllinOne', 5.57, 10, 'test')
But MATLAB returns:
 ??? No method with matching signature.
As you can see, MATLAB incorrectly thinks the signature for the AllinOne method is as follows:
invoke(h) 
AllinOne = [int32, string, int32] AllinOne(handle, double, int32, Variant(Optional))

Best Answer

This problem has been fixed in MATLAB 6.5.1 (R13SP1). If you are using a previous version, read the following:
This issue has been addressed in updated versions of comcli.dll and newprogid.m. With this fix,
the correct signature is seen by MATLAB:
invoke(h) 
AllinOne = [int32, string, int32, Variant] AllinOne(handle, double, int32, Variant(Optional))
You can now invoke methods with optional or reference arguments:
[a,b,c,d] = invoke(h, 'AllinOne', 5.57, 10, 'test')
a =
       1
b =
[out] returned
c =
       20
d =
[out,optional] returned
The updated versions of comcli.dll and newprogid.m should replace the current versions in your MATLAB installation. Both are available from the related solution below.
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