Before it's too late: delegate calling convention

[Gregor Richards]

Jarrett Billingsley wrote:
> "Gregor Richards" <Richards at codu.org> wrote in message 
> news:4548CD75.80803 at codu.org...
> 
> 
>>And a solution that's less nasty: Allow casting of function pointers to 
>>delegate pointers by automatic thunktion generation.
> 
> 
> I like that a lot better.  But if you're wrapping a function pointer in a 
> delegate reference, is a thunk really needed?  I mean, the function won't be 
> accessing the context pointer, so why not just set the delegate's context 
> pointer to null?
> 
> i.e.
> 
> int foo()
> {
> 
> }
> 
> int delegate() bar = cast(int delegate())&foo;
> // bar's function address is &foo, and bar.ptr == null 
> 
> 

The context pointer isn't magic, it's passed as an argument to the 
function. So if you directly casted, you'd end up with an extra argument 
passed to the function, any argument processing would be off-by-one.

  - Gregor Richards