edit1.create

I went and looked at the assembly code for this - you are right - this
will not cause an exception (I even tried it).

The main reason it works is that Delphi does not need a valid object
pointer to call .Free - it is not a virtual method.

If Free were a virtual method, then a valid object pointer would be
required to call free.

Doug

Totoliciu Denis Dan wrote:
When I have posted that the following lines:
>
:= Nil;
Free();
>
do not raise an exception, I didn't have Delphi at
hand; but I knew that inside TFree() it is
written something like this:
>
procedure TFree();
begin
if Self <Nil then
Self.Destroy;
end;
>
The call to Free() through (that is Nil) goes K
because:
1. Free() is not a virtual method; and as we all know,
the binding is done at compile time. That means there
is no need to access a VMT.
2. Every method of a class has a hidden parameter; and
that parameter is Self. When calling Free, there is
no need that is different then Nil as (named
Self inside the method Free()) is passed as parameter.
>
Free() would raise an error when points to a
zone of memory that is not allowed to be accessed.
>