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I didn't think this would work when I typed it in, and sure nuf, it
don't. I'm trying to pass arguments to the constructor of my base
class (a ToggleElem), but I can't figure out how to pass in the slot
(Callback0). 15 lines of code is worth a million words: class ToolbarMenuElem : public Gtk::Toolbar_Helpers::ToggleElem { public: ToolbarMenuElem( Gtk::Menu * menu_, const Glib::ustring & text, Gtk::Widget & content, const Glib::ustring & tooltip_text=Glib::ustring(), const Glib::ustring & tooltip_private_text=Glib::ustring()); } ToolbarMenuElem::ToolbarMenuElem( Gtk::Menu * menu_, const Glib::ustring & text, Gtk::Widget & content, const Glib::ustring & tooltip_text, const Glib::ustring & tooltip_private_text) : Gtk::Toolbar_Helpers::ToggleElem(text, content, SigC::slot(*this, &ToolbarMenuElem::on_toggled), tooltip_text, tooltip_private_text) { ... } I'm getting a very odd compiler error that points to header files in SigC++, but I'm pretty sure it comes back to me trying to use *this in the argument list for the base class constructor call. Questions: 1) Is there any way to accomplish what I'm trying to do? 2) If not, how do I generate a NULL slot to appease compilation? I think I can hook up the the toggled signal after I'm off and running. I tried like hell, but couldn't come up with the magic string of greek C++ to make the compiler happy. 3) When does 'this' come into existence? Shouldn't it be the first argument in the call to ToolbarMenuElem::ToolbarMenuElem(...), and therefore, available for use in the base class constructor call? i.e., at the time of the call to the ToolbarMenuElem constructor, the memory has been allocated and a pointer to it should exist, right? 4) Is this a bug/feature-request for gtk/gtkmm? Am I doing something I shouldn't be trying to do? Gtkmm brags about the ability to derive from Gtk objects. What gives? Maybe we just need a constructor that doesn't require a Callback0. Trust me, I'll hook one up later (if I feel the need)! 5) Why can't anything ever go smoothly :( ? Much appreciation in advance! I'm at a brick wall here. Work-arounds in my head right now totally defeat the purpose of C++. Here's the (un-intelligible?) compiler error message: || In file included from /usr/include/sigc++-1.2/sigc++/object_slot.h:73: || /usr/include/sigc++-1.2/sigc++/object_slot.h: In constructor || `SigC::ObjectSlotNode::ObjectSlotNode(void (*)(void*), T*, void*, T2) [with || T = ToolbarMenuElem, T2 = void (ToolbarMenuElem::*)()]': /usr/include/sigc++-1.2/sigc++/slot.h|211| instantiated from `SigC::Slot0<R>::Slot0(SigC::SlotNode*) [with R = void]' /usr/include/sigc++-1.2/sigc++/object_slot.h|73| instantiated from `SigC::Slot0<R> SigC::slot(O1&, R (O2::*)()) [with R = void, O1 = ToolbarMenuElem, O2 = ToolbarMenuElem]' ToolbarMenuElem.cc|14| instantiated from here /usr/include/sigc++-1.2/sigc++/object_slot.h|45| no matching function for call || to `SigC::ObjectSlotNode::init(ToolbarMenuElem*&, void*&, void || (SigC::Object::*&)())' /usr/include/sigc++-1.2/sigc++/object_slot.h|46| candidates are: void || SigC::ObjectSlotNode::init(SigC::Object*, void*, void (SigC::Object::*)()) || In file included from /usr/include/sigc++-1.2/sigc++/object_slot.h:187: || /usr/include/sigc++-1.2/sigc++/object_slot.h: In constructor || `SigC::ObjectSlotNode::ObjectSlotNode(void (*)(void*), T*, void*, T2) [with || T = ToolbarMenuElem, T2 = void (ToolbarMenuElem::*)(int&, int&, bool&)]': /usr/include/sigc++-1.2/sigc++/slot.h|343| instantiated from `SigC::Slot3<R, P1, P2, P3>::Slot3(SigC::SlotNode*) [with R = void, P1 = int&, P2 = int&, P3 = bool&]' /usr/include/sigc++-1.2/sigc++/object_slot.h|187| instantiated from `SigC::Slot3<R, P1, P2, P3> SigC::slot(O1&, R (O2::*)(P1, P2, P3)) [with R = void, P1 = int&, P2 = int&, P3 = bool&, O1 = ToolbarMenuElem, O2 = ToolbarMenuElem]' ToolbarMenuElem.cc|28| instantiated from here /usr/include/sigc++-1.2/sigc++/object_slot.h|45| no matching function for call || to `SigC::ObjectSlotNode::init(ToolbarMenuElem*&, void*&, void || (SigC::Object::*&)())' /usr/include/sigc++-1.2/sigc++/object_slot.h|46| candidates are: void || SigC::ObjectSlotNode::init(SigC::Object*, void*, void (SigC::Object::*)()) || make: *** [ToolbarMenuElem.o] Error 1 |