Re: [gtkmm] compilation error due to a signal connect

[Roger Leigh <roger whinlatter uklinux net>]

cedric <cedric probesys com> writes:

> Roger Leigh a écrit :
>
>>cedric <cedric probesys com> writes:
>>
>>
>>
>>>hi!
>>>i m a newbie on gtkmm and i have a little (BIG ;-/ ) problem:
>>>
>>>i ve made a class "test". in the constructor, i create a
>>>Gtk::Menu::MenuElem MenuName, and i want to connect it with a function
>>>"print". it works only and only if this "print" function is declared
>>>as static, because if i declare it virtual (or even without virtual)
>>>and not static, i have a compilation error :
>>
>>>                         SigC::slot(&test::print) ); //here is the problem!
>>
>>A pointer to a class member function requires a reference to the class
>>as well as the method:
>>
>>    SigC::slot(*this, &test::print) );

> i ve just forgotten to put it in my mail, but it was in my source!
>
> because if i declare "print" as "static void print();" and if i put also
>
> "...SigC::slot(&test::print) );", it works ! and i forgot to reput "*this"!
> sorry for my mistake! but the problem still remains :'(

If print() is static, then you can use

  SigC::slot(&test::print)

because there's no this pointer (it's not a class instance, i.e. an
object).  It's equivalent to creating a slot from a function.  If you
remove the static keyword, and try

  SigC::slot(*this, &test::print)

you should find it works.

If it doesn't work, post a short compilable example that exhibits the
problem.  The code you posted isn't meaningful on its own.

I suggest you have a read of the libsigc++ documentation.  It explains
how all the signal and slot stuff works, with simple examples.  You
can get the signalling concepts working before touching gtkmm.

The gtkmm book also has examples of menus.


-- 
Roger Leigh

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