>>I don't think you do. There are languages that permit you to pass an object by value; this means that the receiving function/method gets the address of a copy of the object, as opposed to the address of the copy of an object pointer value. The object passed by value in this case would have a lifespan of the parameter's validity, as opposed to an object reference passed by value as is the case with VFP pass by value, as opposed to the address of the object pointer, the case of VFP's pass by reference. And you absolutely need to understand this difference, since it's an important concept for little unimportant issues like COM!
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>Ed, that is a very unclear way of explaining something. Normally, showing different cases and the details of that case would be more effective. Regardless, why even talk about passing by value when it isn't done in VFP with objects? You either pass a pointer, or a pointer to a pointer. Right?
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Let's examine this in the context of COM marshalling. What is actually passed to a remote server, and what behavior occurs when the value passed to the method is passed by reference vs passed by value? Because of marshalling, the "pointer" is never passed directly, is it?
>Anyways, this is not the original point. You said "To actually pass an object by value, you'd have to create a copy of the object in the calling code and destroy the created object copy on return." If you are creating the copy and then working with that copy, you are not really passing by value. You are passing by reference to the COPY. So sure, you can manipulate and change the COPY without changing the original object. But you are only simulating passing the original by value, you are not actually doing it. But your meaning is understood.
Answer the following. If I pass a char memvar by reference, what is passed? If I pass a char memvar by value, what is passed? Realize that the recieving code doesn't know, and doesn't care, if a byref or byval occurred. It receives the same thing in both cases, a parameter of unspecified type and context...
