On Sat, Dec 14, 2013 at 6:26 AM, Antony Pavlov <antonynpav...@gmail.com> wrote: > Hi, Andreas! > > Here is a quote from http://wiki.qemu.org/QOMConventions > >> a FooClass structure definition containing at least the parent class >> field: >> >> typedef struct { >> /*< private >*/ >> MyParentClass parent_class; >> /*< public >*/ >> >> [any fields you need] >> } FooClass; > > What do the "< private >" and "< public >" comments exactly mean here?
Private means inaccessible to everybody, including the implementation of class being instantiated. No one should ever dereference a private variable, they should be managed by QOM indirectly via casts if needed. Public means that at least someone can access it. Note that public does not declare a free-for-all. QOM class variables may be "public" in the sense that the class implementation may access them. Container devices however still can not, and they are private from that point of view. For example, a timer peripheral may have a "public" ptimer, in the sense that the timer class derefences and modifies the timer for its implmentation. An embedding SoC device however can NOT use this despite being public, its private to the timer implementation. So in short: < /* private */ > - owned by the QOM framwork - do no dereference ever from anywhere. < /* public */> - owned by the class implementation - do not dereference from containers. There is also automated documentation generation using this. Regards, Peter > > -- > Best regards, > Antony Pavlov >
