Marshalling of remotable handles

[Rob Shearman]

2008/12/21 Michael Karcher <wine at mkarcher.dialup.fu-berlin.de>:
> Hello Wine developers,
>
> while trying to add proxy/stub code for shell32, I stumbled across the
> definition of remotable handles in IDL.
>
> We have
>
>  - a RemotableHandle union.
>  - the IDL typedefs for the wire representation of handles:
> |    typedef [unique] RemotableHandle *wireHXXX;
>  - the IDL declaration for the handle types itself:
> |    typedef [wire_marshal(wireHXXX)] void*HXXX;
>
> This makes widl generate null pointer checks for HWND parameters, as
> HXXX is a void pointer without the unique attribute. My question is:
> Should widl really add this check? As the type is marshalled as
> wireHXXX, the null value is no problem for marshalling, so it could be
> safely left out.

Yes, that's a widl bug - it shouldn't output NULL ref pointer checks
for user-marshaled types.

> What I did in my repository was adding the [unique] attribute to the IDL
> typedef of the handle type:
> | typedef [unique, wire_marshal(wireHXXX)] void*HXXX;
> Is this the right approach to generally get rid of the NULL pointer
> checks for handles, or is widl to be fixed instead?

widl should be fixed, since MIDL correctly doesn't output NULL ref
pointer checks when using the same source IDL files.

-- 
Rob Shearman