Targetted signals

Thiago Macieira thiago.macieira at
Wed Jun 7 11:48:50 PDT 2006

Daniel P. Berrange wrote:
>Actually I think if you set an explicit destination on the signal it
> will do the right thing - ie unicast to that recipient only.

But the signal may multicast to many different objects and listeners 
inside that recipient, so I would imagine this is a dangerous feature.

Imagine that we decide to merge two services in one daemon later. They 
could share the same D-BUS connection, so they'd still receive the signal 

>The only problems I remember having with setting an explicit
> destinations are:
> * In the context of method calls - you can set a destination to be a
>   well known bus name (org.example.blah), but it wouldn't let me set a
>   destination based on unique name (:1.2).

This sounds like a bug, but right now all of the calls I place are done 
with a unique name. So I something may be wrong in your code.

> * Signal match rules - you can register a match rule based  on a unique
>   bus name (:1.2), but not one based ona well known bus name
>   (org.example.blah).

True, this is an important feature. If you want to receive a signal from a 
specific bus name, you need to listen for the NameOwnerChanged signal and 
update the unique connection your match rule points to.

Thiago José Macieira - thiago.macieira AT
Trolltech AS - Sandakerveien 116, NO-0402 Oslo, Norway
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