Re: g_signal_lookup for interfaces

[James Henstridge <james daa com au>]

Bill Haneman wrote:

> Hi:
>
> I guess this one is for you, Tim...
>
> We have defined a number of signals in ATK on interfaces.  We know we 
> can't define properties on interfaces now, but we have been using 
> signals on interfaces, which is supported.
>
> However in order to intercept these signals we need to register an 
> emission hook.  In the bridge to at-spi this is done via a string-based 
> register call containing the names of the signal and type.
> [where type_name = "AtkText", signal_name = "text-caret-moved"]
>
> GType *type = g_type_from_name(type_name);
>
> However, if we call 
>
> g_signal_lookup (signal_name, type); 
Calling the atk_text_get_type() function for your interface doesn't 
guarantee your atk_text_base_init() function will be called (this is 
delayed til the first time the interface is used (ie. getting the class 
pointer for a type implementing the interface).  Not sure how best to 
force the interface to initialise though.  For GObject subclasses, it is 
as simple as:
 class = g_type_class_ref(type);
 id = g_signal_lookup(name, type);
 ...
 g_type_class_unref(class);

James.