Re: How to use a signal

["Jamiil Abduqadir" <jalqadir gmail com>]

Thanks Jose for your prompt response!
I have two questions regarding this issue,
One: what does HTH mean and 
Second:
After doing the modifications your suggested, as shown below, I now get this 3 errors, please at the end of this message.

Please note, that this is the first time I am developing a GUI
interface, I have chosen Gtkmm because it is C++, portable and fast,
nevertheless, I might make stupid mistakes just because of my poor
understanding of the GUI library, not because my lack of understanding
of the OOP paradigm. As it is the case now, I am sure that I am not
passing the right parameters expected by Gtkmm. However, according to 

c:\doc\gtkmm-2.4/docs/tutorial/html/apb.html#id2567896

these, and as far as I understand, are the two parameters that I have to pass.

What am I doing wrong?

Thanks in advance.


================ code snip ========
namespace jve{
class Entry: virtual public Gtk::VBox {
      .......
      Gtk::Entry* text_box;
public:
      MyClass();
      .........
      void onBlanck();
};
}
jve::Entry::Entry(){
      ....
      text_box  = Gtk::manage(new Gtk::Entry());
      text_box->signal_focus_out_event().connect(sigc::mem_fun(*this, &Entry::onBlank)); <== here is the problem

      ....
}
void jve::Entry::onBlank(){ // this->getText() returns a Gtk::ustring object
   if(this->getText(().empy()){
      // Display a Dialogbox explaining the problem
      text_box->grab_focus();
   }
}

=========== errors ===========

||=== Console application, default ===|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|144|instantiated from
`static void*(* sigc::internal::slot_call1<T_functor, T_return,
T_arg1>::address())(void*) [with T_functor =
sigc::bound_mem_functor0<void, jme::Entry>, T_return = bool,
T_arg1 = GdkEventFocus*]'|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|529|instantiated from
`sigc::slot1<T_return, T_arg1>::slot1(const T_functor&) [with
T_functor = sigc::bound_mem_functor0<void, jme::Entry>, T_return
= bool, T_arg1 = GdkEventFocus*]'|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|1157|instantiated
from `sigc::slot<T_return, T_arg1, sigc::nil, sigc::nil, sigc::nil,
sigc::nil, sigc::nil, sigc::nil>::slot(const T_functor&) [with
T_functor = sigc::bound_mem_functor0<void, jme::Entry>, T_return
= bool, T_arg1 = GdkEventFocus*]'|

D:\c++\Samiira\entry.cpp|12|instantiated from here|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|136|error: void value not ignored as it ought to be|

D:\XWin\include\sigc++-2.0\sigc++\adaptors\adaptor_trait.h||In member
function `typename
sigc::adaptor_functor<T_functor>::deduce_result_type<T_arg1,
void, void, void, void, void, void>::type
sigc::adaptor_functor<T_functor>::operator()(T_arg1) const [with
T_arg1 = GdkEventFocus* const&, T_functor =
sigc::bound_mem_functor0<void, jme::Entry>]':|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|136|instantiated from
`static T_return sigc::internal::slot_call1<T_functor, T_return,
T_arg1>::call_it(sigc::internal::slot_rep*, typename
sigc::type_trait<T_arg3>::take) [with T_functor =
sigc::bound_mem_functor0<void, jme::Entry>, T_return = bool,
T_arg1 = GdkEventFocus*]'|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|144|instantiated from
`static void*(* sigc::internal::slot_call1<T_functor, T_return,
T_arg1>::address())(void*) [with T_functor =
sigc::bound_mem_functor0<void, jme::Entry>, T_return = bool,
T_arg1 = GdkEventFocus*]'|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|529|instantiated from
`sigc::slot1<T_return, T_arg1>::slot1(const T_functor&) [with
T_functor = sigc::bound_mem_functor0<void, jme::Entry>, T_return
= bool, T_arg1 = GdkEventFocus*]'|

D:\XWin\include\sigc++-2.0\sigc++\functors\slot.h|1157|instantiated
from `sigc::slot<T_return, T_arg1, sigc::nil, sigc::nil, sigc::nil,
sigc::nil, sigc::nil, sigc::nil>::slot(const T_functor&) [with
T_functor = sigc::bound_mem_functor0<void, jme::Entry>, T_return
= bool, T_arg1 = GdkEventFocus*]'|

D:\c++\Samiira\entry.cpp|12|instantiated from here|

D:\XWin\include\sigc++-2.0\sigc++\adaptors\adaptor_trait.h|84|error: no
match for call to `(sigc::bound_mem_functor0<void, jme::Entry>)
(GdkEventFocus* const&)'|

D:\XWin\include\sigc++-2.0\sigc++\functors\mem_fun.h|1787|note:
candidates are: T_return sigc::bound_mem_functor0<T_return,
T_obj>::operator()() const [with T_return = void, T_obj =
jme::Entry]|

D:\XWin\include\sigc++-2.0\sigc++\adaptors\adaptor_trait.h|84|error:
return-statement with a value, in function returning 'void'|

||=== Build finished: 3 errors, 0 warnings ===|
-- 
Happiness
has many doors, and when one of them closes another opens, yet we spent
so much time looking at the one that is shut that we don't see the one
that just opened.