On Thu, Sep 20, 2012 at 12:32 PM, William Henry <whe...@redhat.com> wrote:
> > > ----- Original Message ----- > > How about: > > > > int pn_messenger_subscribe(pn_messenger_t *messenger, const char > > *source, > > void* context); > > This one I like. It makes a lot of sense. > > > void *pn_message_subscribe_context(pn_message_t *msg); > > > > This one less so. I have to make an extra call after I receive the > message. Then the implementation needs to do some sort of lookup. I think > it would be much more efficient if I had an API that returned the message > and the context. > I can't imagine there would be a significant difference in efficiency in any real world scenario. The internal mechanism to find the context should be exactly the same either way, and setting the context in an out parameter vs setting a slot on the message are both just pointer indirection. The only difference would be the procedure call overhead associated with actually accessing the pointer stored inside the message, and if that starts being an issue then I think (a) we have much bigger trouble since that's how all the fields inside a message are accessed, and (b) we're totally awesome because we must have done an impossibly great job of optimizing the rest of the code for this to even show up on a profile. ;-) --Rafael
