On Tue, 2007-09-25 at 13:30 +0100, Dave Howorth wrote: > > the convention in gtk+ is that any changed signal is emitted at least > > once when "something" changes: there's no upper bound, just the lower > > one[1]. > > Hmm, I click on a button to make a bank transfer and the transfer > happens twice? I saw this issue once in an inter-bank transfer system.
this has *nothing* to do with gtk+, so please don't use it as an argument. the convention is defined and documented in countless threads (even on this very mailing list :-)), and as such gtk+ has always had this kind of behaviour; some applications might even depend on it - so it's not going to change. you can use pre-conditions and post-conditions to verify the data before committing it inside the callback - as you always should, since it's dealing with user input. > > > will result in your callback not being invoked[2]; you can use this > > inside the callback of the other widget that controls the contents of > > the entry. > > AFAICT, this would mean that my callback is not called at all. yes. if you are changing the content of the entry with a known value then you can also call the functions you are calling in the GtkEntry::changed callback as well. if you can't do that it means you haven't separated the logic of the application from the UI code - and this is usually something that bites you back, sooner or later. > > [1] I think there's a bug open, somewhere in bugzilla, for this specific > > instance (making a set_text() atomic); personally, I think it's merely a > > matter of taste: the ::changed signal convention is known and > > documented. > > It's not documented where it's needed! (i.e. at > <http://library.gnome.org/devel/gtk/unstable/GtkEditable.html#GtkEditable-changed> > and/or > <http://library.gnome.org/devel/gtk/unstable/GtkEntry.html#gtk-entry-set-text>) then, please: provide a patch for the gtk+ upstream documentation. those patches are usually applied as soon as received. see, for instance: http://mail.gnome.org/archives/gtk-devel-list/2004-June/msg00085.html In general, "changed" signals should be thought of as "something might have changed" rather than as "something changed". ciao, Emmanuele. -- Emmanuele Bassi, W: http://www.emmanuelebassi.net B: http://log.emmanuelebassi.net _______________________________________________ gtk-perl-list mailing list gtk-perl-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-perl-list
