PropertiesChanged signal, take 2

Lennart Poettering mzqohf at
Wed May 12 12:49:28 PDT 2010

On Wed, 12.05.10 15:41, David Zeuthen (zeuthen at wrote:

> Hey,
> On Wed, May 12, 2010 at 2:58 PM, Thiago Macieira <thiago at> wrote:
> > How do you detect whether the signal is implemented? You have to parse the
> > remote object's introspection?
> Yup, that's one option. The spec wording is that if you include the
> signal in the introspection XML, then you promise to emit it (except
> for properties you opt out with using the annotation).

Hmm, Could we extend this a little so that we can set the annotation on
the class interface itself too, to set a default for the interface that
is then overridable per-property? In systemd I have a metric truckload
of properties on each service, which means that the introspection data
is already kinda big, and instead of annotating every single property as
EmitsChangedSignal=true_no_value I'd prefer having to annotate that only
once for the interface. Makes the introspection XML blurb smaller and
more readable.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net           GnuPG 0x1A015CC4

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