Abstract classes vs interfaces, casting from void*
john.loughran.colvin at gmail.com
Fri Aug 9 13:21:54 UTC 2019
On Friday, 9 August 2019 at 13:19:14 UTC, kinke wrote:
> On Friday, 9 August 2019 at 12:26:59 UTC, John Colvin wrote:
>> Why is there no "hi" between 0 and 1?
> Because you are treating the unadjusted object pointer as
> interface pointer and then call the only virtual function of
> that interface, in the 2nd vtbl slot (after the TypeInfo ptr).
> Casting a class ref to an interface offsets the pointer, so
> that the interface ref points to the interface vptr for that
> object instance. This is missing in that line, and so you are
> invoking the first virtual function of class C, which is some
> base function in `Object`.
Ok, makes sense, thanks.
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