🚀 go-pugleaf

In article <pauld.767898877@sarge>, pauld@verdix.com (Paul Durbin) writes:
>I attempt to use a member function as callback but all three arguments (to the
>callback) are garbage. If I make it a friend then the arguments are correct,
>but then I can't get to the class data, without reference thru an instance of
>the class and I don't want the data to be static.
>
>So, what is causing this problem? Could I possibly use the *this pointer as
>the client_data to the callback, then cast to the appropriate class?
>
>thanks in advance for all the wonderful help.

Try a  static  member function and pass  this  in the client data.

	class foo
	{
		public :
		bar ();

		private :
		static void _bar ( Widget, XtPointer, XtPointer );
	}

	foo::_bar ( Widget, XtPointer, closure )
	{
		foo* fooP = (foo*) closure;
		fooP->bar ();
	}

	foo::mumble ( ... )
	{
		XtAddCallback ( ..., _bar, this );
		/* Or: ... (XtPointer) this */
	}


	--- Allan.

<ENGELHARDT@alonl.cern.ch>