On Tue, 2005-11-29 at 14:56 +0100, Dick Eimers wrote: > > A dynamic_cast<> should allow this. You'd need lots of them, in an > > if/else-if block, for each sigc::signal<> type that you expect. > > It turns out that the dynamic_cast fails because sigc::signal_base has > no virtual functions (not even a virtual destructor).
That's interesting, and a pity if it's true. > And, of course, > at least one virtual function needs to be defined in a class to be able > to use the dynamic_cast<> cast. > > The reason is probably to optimize for speed, but is it really that > important and more important than being extensible and allow for > type-safe downcasting? People do get obsessed with optimisation, yes. But, anyway, we couldn't change this now, without breaking ABI. I suggest that you a) Store a second piece of information alongside each signal, identifying the signal type. b) Use static_cast<>, after you've discovered what the type is. -- Murray Cumming [EMAIL PROTECTED] www.murrayc.com www.openismus.com _______________________________________________ libsigc-list mailing list libsigc-list@gnome.org http://mail.gnome.org/mailman/listinfo/libsigc-list
