linuxaudio.org

On Fri, Sep 2, 2011 at 10:22 AM, David Robillard  wrote:

quoted text
>> >

>> > The main issue you'll find with going the C++/RTTI route is that #2 no

>> > longer is possible, since virtual objects are not POD, so you can't

>> > safely write them through a ringbuffer (or copy them around manually in

>> > general).

>> [snip]

>>

>> Correct me if I'm wrong... but...

>>

>> >>       class event_two_t : public event_t

>> >>       {

>> >>       public:

>> >>           int type() { return int(EVENT_TWO); }

>> >>           uint32_t size() { return sizeof(event_two); }

>> >>

>> >>           /* event-specific stuff */

>> >>       };

>>

>> The intention of the size() member function is to allow you to memcpy()

>> the object without knowing its type.  Is that not enough?

>

> Because it uses inheritance, this object is not POD, so strictly

> speaking no.

Yes, it's not strictly POD.  However, the objective was to have an

RT-safe way to pass almost-POD objects in the confines of a

single-process, shared-memory application.  In this situation, I think

the the fact that the vtable is not POD is a non-issue because the

pointers are all valid, static references.
However, if he needs some manner of IPC, serialization, or plugin

(loading/unloading code) scheme... then this is indeed a show stopper.
-gabriel

_______________________________________________

Linux-audio-dev mailing list

Linux-audio-dev@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-dev