Paolo Bonzini <pbonz...@redhat.com> writes: > Il 28/05/2013 19:32, Michael S. Tsirkin ha scritto: >>>> > > + >>>> > > + switch (addr) { >>>> > > + case offsetof(struct virtio_pci_common_cfg, >>>> > > device_feature_select): >>>> > > + return proxy->device_feature_select; >>> > >>> > Oh dear no... Please use defines like the rest of QEMU. >> Any good reason not to use offsetof? > > I'm not sure it's portable to use it in case labels. IIRC, the > definition ((int)&(((T *)0)->field)) is not a valid C integer constant > expression. Laszlo?
It's defined to yield an integer constant expression in the ISO standard (and I think ANSI too, though that's not at hand): 7.19, para 3: ...offsetof(type, member-designator) which expands to an integer constant expression that has type size_t, ... The real question is whether compilers qemu cares about meet the standard (there's some evidence that older compilers fail this). If not, we'll have to define them as raw offsets... Cheers, Rusty. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html