PropertiesChanged signal

Lennart Poettering mzqohf at
Fri May 7 10:46:41 PDT 2010

On Fri, 07.05.10 13:06, David Zeuthen (zeuthen at wrote:

> Now for a subjective view: If you examine the D-Bus services on a
> typical Linux desktop, you will find that a lot of them don't use
> properties when "they should". Which is too bad, because it makes
> things harder to debug, for example, you have to call GetXYZ() instead
> of just using d-feet or gdbus(1) (see [0] below again) to quickly
> inspect the property XYZ. I think the existence of the
> PropertiesChanged() signal, plus the availability of bindings
> supporting it (such as GDBus), will make it a lot more appealing for
> D-Bus service authors to use D-Bus properties when "they should".

Hmm, could we extend the spec a little and say that a PropertiesChanged
signal with an empty dict means "some property changed"? I know quite a
few projects which have something like this (and for a reason, since the
property data is big and more often not read than it is read), including
some of my own. This minor extension to your suggestion would allow me
to follow your spec without a headache of sending more data over the bus
than necessary.


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

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