Juan Quintela wrote: > vstrucut virtio_common *create_virtio_comon(...., size we really want); > Again, this implements superclass/subclass as well as you can implemnt > it in C.
It would be more type-safe for create_virtio_common() to be a macro taking the subclass *type* rather than sizeof. And it would make the calls short: No need to cast the result, because the macro would return the desired type (doing the cast itself). #define create_virtio_common(...., type) \ ((type *)_create_virtio_common(...., sizeof(type))) Once you have that, it's easy to change to add a field name and container_of: #define create_virtio_common(...., type, field) \ (container_of(_create_virtio_common(...., sizeof(type)), type, field)) That gives you malloc in common init, and type-safe callers everywhere (no possibility for mistaken sizeof). I think it's a simpler to use API and better at protecting against caller mistakes; you may disagree. -- Jamie
