Re: noob question: g_signal_connect()

[David NeÄas <yeti physics muni cz>]

On Tue, Mar 06, 2012 at 10:07:16AM -0900, Christopher Howard wrote:
> Hi. I've installed the api documentation from the source code for both
> gtk+ and glib, but I can't seem to find an api description of
> g_signal_connect().

http://developer.gnome.org/gobject/stable/gobject-Signals.html#g-signal-connect

> ----------
>   g_signal_connect (G_OBJECT (button[0]), "draw",
>                 G_CALLBACK (draw_callback), NULL);
> ----------
>
> Could somebody please explain two things:
>
> 1) What is the purpose of the string in the second position in the
> parameter list?

That is the signal name â the same as listed in Signals section in the
description of each object.

> 2) What is the purpose of the fourth parameter slot, with the NULL in
> it? Can other options go there?

It is a pointer that the callback function will get as its last
argument.  You can use it to pass additional data to the callback.

Yeti