Re: [sigc] compilation problems

["Nicholas Penwarden" <penwan cs wisc edu>]

You are not emitting signals correctly. This is the typesafety of a
signals and slots system like libsigc++ helping you out :)

For example, you define the onCreate signal as such:

sigc::signal<bool, dtk::widget, void*> onCreate

This means that any slot connected to it must take a dtk::widget and
void * as parameters and return a boolean. It also means that when you
emit the signal, you need to pass a dtk::widget and a void * to the
signal. So:

widget::widget(void)
{
    onCreate(this, 0);
}

Note that this will NOT compile either. I'm passing a dtk::widget * in
to the signal, not a dtk::widget. I'm assuming thats what you mean to
do (or perhaps a dtk::widget &). If you were to pass a dtk::widget in,
a copy of the widget would be created and passed in. And since you
don't define a copy constructor, the default constructor would be
called...which would emit the signal, which would call a constructor,
which would emit a signal, etc.

Basically, you have to give the proper parameters to the signal when you emit.

Nick

On 3/7/06, masse_nicolas yahoo fr <masse_nicolas yahoo fr> wrote:
> sorry if my question is stupid but, why does libsigc++ not work for me?
>
> Here is the files I use:
> The Header:
> ...
> #include <sigc++/sigc++.h>
>
> namespace dtk
> {
>
> typedef enum {
>         DTK_WDG_HIDED = 0,
>         DTK_WDG_SHOWN = 1
> }wdg_state;
>
> class widget : protected eventReceiver
> {
>
>         public:
>                 widget();
>                 virtual ~widget();
>                 virtual void draw();
>                 virtual void redraw(int width=0, int height=0);
>                 virtual void show();
>                 virtual void hide();
>                 virtual void dock(IDirectFBSurface& dfb_surface);
>                 virtual IDirectFBSurface* undock();
>
>                 //Slots
>                 sigc::signal<bool, dtk::widget, void*> onCreate;
>                 sigc::signal<bool, dtk::widget, void*> onDestroy;
>                 sigc::signal<bool, dtk::widget, void*> onDraw;
>                 sigc::signal<bool, dtk::widget, void*> onShow;
>                 sigc::signal<bool, dtk::widget, void*> onHide;
>                 sigc::signal<bool, dtk::widget, void*> onDock;
>                 sigc::signal<bool, dtk::widget, void*> onUndock;
>                 //Actions
>                 //None for the moment
> ....
>
> The Implementation:
>
> #include "widget.h"
>
> namespace dtk
> {
>
> widget::widget()
> {
>         onCreate();
> }
>
>
> widget::~widget()
> {
>         onDestroy();
> }
>
> ...
>
> And when I try to compile my file, here is the result:
> if g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"DTK\" -DVERSION=\"0.0.1\"  -I. -I. -D_REENTRANT -I/usr/include/++dfb -I/usr/include/directfb   -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include   -DDATADIR=\"/usr/share\" -DPACKAGE=\"DTK\"   -Wall -O2 -pipe  -MT widget.o -MD -MP -MF ".deps/widget.Tpo" -c -o widget.o widget.cpp; \
> then mv -f ".deps/widget.Tpo" ".deps/widget.Po"; else rm -f ".deps/widget.Tpo"; exit 1; fi
> event.h:31: warning: 'class dtk::eventReceiver' has virtual functions but non-virtual destructor
> widget.cpp: In constructor 'dtk::widget::widget()':
> widget.cpp:29: error: no matching function for call to 'sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>::emit()'
> /usr/include/sigc++-2.0/sigc++/signal.h:1923: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::emit(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> widget.cpp: In destructor 'virtual dtk::widget::~widget()':
> widget.cpp:35: error: no match for call to '(sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>) ()'/usr/include/sigc++-2.0/sigc++/signal.h:1927: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::operator()(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> widget.cpp: In member function 'virtual void dtk::widget::draw()':
> widget.cpp:42: error: no match for call to '(sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>) ()'/usr/include/sigc++-2.0/sigc++/signal.h:1927: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::operator()(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> widget.cpp: In member function 'virtual void dtk::widget::redraw(int, int)':
> widget.cpp:49: error: no match for call to '(sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>) ()'/usr/include/sigc++-2.0/sigc++/signal.h:1927: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::operator()(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> widget.cpp: In member function 'virtual void dtk::widget::show()':
> widget.cpp:56: error: no match for call to '(sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>) ()'/usr/include/sigc++-2.0/sigc++/signal.h:1927: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::operator()(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> widget.cpp: In member function 'virtual void dtk::widget::hide()':
> widget.cpp:63: error: no match for call to '(sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>) ()'/usr/include/sigc++-2.0/sigc++/signal.h:1927: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::operator()(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> widget.cpp: In member function 'virtual void dtk::widget::dock(IDirectFBSurface&)':
> widget.cpp:70: error: cannot convert 'IDirectFBSurface**' to 'IDirectFBSurface*' in assignment
> widget.cpp:71: error: no match for call to '(sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>) ()'/usr/include/sigc++-2.0/sigc++/signal.h:1927: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::operator()(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> widget.cpp: In member function 'virtual IDirectFBSurface* dtk::widget::undock()':
> widget.cpp:80: error: no match for call to '(sigc::signal<bool, dtk::widget, void*, sigc::nil, sigc::nil, sigc::nil, sigc::nil, sigc::nil>) ()'/usr/include/sigc++-2.0/sigc++/signal.h:1927: note: candidates are: typename sigc::internal::signal_emit2<T_return, T_arg1, T_arg2, T_accumulator>::result_type sigc::signal2<T_return, T_arg1, T_arg2, T_accumulator>::operator()(typename sigc::type_trait<T_derived>::take, typename sigc::type_trait<T_arg3>::take) const [with T_return = bool, T_arg1 = dtk::widget, T_arg2 = void*, T_accumulator = sigc::nil]
> make[1]: *** [widget.o] Error 1
>
>
> Can someone help me?
> Many thanks.
>
> Ps: I'm using gcc-4.0.2 on a gentoo box, don't know if it change something
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