Re: [Xen-devel] pointers in public headers

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>Io/xs_wire.h does not define a hypervisor interface so no need for guest
>handles there.

Good.

>The rest are all x86-specific, and represent pointers that
>don't really cleanly fit into the guest handle model and its accessor
>macros. Since on x86 the guest handle stuff is really only an enforcement
>method for ensuring we use the correct accessors I just left the tricky few
>as they were. Are you trying to macro/typedef the world for compat
>compilation, and these are annoying for you? :-) If so we could hide them
>behind a different macro -- we'd need to do that anyway to avoid breaking
>API compatibility.

Yes, they present a lurking problem once the converted structures get
accessed - clearly any kind of pointer is invalid when considering compatibility
mode guests. I could certainly try to make the script catch them and convert
them (to a integer type), but then the automation of copying the respective
fields will trigger compiler warnings about converting integrals to/from
pointers of different size.
So, yes, some kind of macro would help, but I can't see how you would
want to get away with not breaking API compatibility (which requires to
leave a pointer in there somehow) but eliminating the pointer.

Jan

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