Re: strangeness of g_signal_connect

[Owen Taylor <otaylor redhat com>]

On Mon, 2005-07-25 at 12:50 +0530, Annamalai Gurusami wrote:
> Colossus <colossus 3000 it> writes:
>
> > In my app I have the following:
> >
> > g_signal_connect ((gpointer) AddFile_button, "clicked",
> >                      G_CALLBACK (on_add_files_activate),
> >                      "dummy");
>
> I normally write the above call like this:
>
> g_signal_connect( G_OBJECT(AddFile_button), "clicked",
>                   G_CALLBACK(on_add_files_activate), "dummy");
>
> Are both correct?  Which is the preferred way to do it?

Unless you are programming in C++, either will work, since there
is an automatic cast from any type to a void *, which is what
the first argument of g_signal_connect() takes. In C++, you need
the first.

My preference is simply:

 g_signal_connect (AddFile_button, "clicked",
                   G_CALLBACK (on_add_files_activate), "dummy");

The reason that g_signal_connect() takes a void * rather than
a GObject * for the first parameter is that you could, in theory,
have libgobject types not deriving from GObject that supports
signals. In practice, I don't know of any uses of that.

Regards,
                                                Owen