setting object properties in matlab classes

Hi there, I have a very simple question. Is it not possible in matlab to modify an objects properties in a function? I am seeing strange results, but I am sure I am doing something wrong. below is a simple class. I multiply the property value "prop" by 2 inside the function addEntry, but it doesnt reflect in the object once it exits the function. Can anyone help?

classdef dummyclass 
    properties
        prop
    end
    methods
        function obj = dummyclass()
            obj.prop=1;
        end
        function flag = addEntry(obj)
            obj.prop=obj.prop*2;
            obj.prop
            flag = 1;
        end
    end

end
q=dummyclass;
q.prop
q.addEntry()
q.prop

Answer 1

[Walter Roberson]

Unless you are using an object derived from the handle class, a copy of the object is modified. You have to return the modified object and store that over the original object.

        function [obj, flag] = addEntry(obj)
            obj.prop=obj.prop*2;
            obj.prop
            flag = 1;
        end

and in user code,

[MyObj, flag] = MyObj.addEntry();

[ABAK]

Thanks, that makes sense.

instead of doing what you are suggesting, can you point me in the right direction on setting this up correctly? i.e. creating a handle class and deriving from it? Its quite lame to create copies unnecessarily

[Walter Roberson]

http://www.mathworks.com/help/techdoc/matlab_oop/brfylq3.html