Questions about the session dbus

[otacon14112]

1. I've been learning how to use dbus lately in Qt. After writing a program that lists all the services available on dbus, I introspected them and a couple showed that they had public methods available. However, the vast majority of them, both with the well-known names, and the unique names, displayed

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<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node>
</node>

which, to me, seems like they have 0 public methods available.

From various articles I've read, they made dbus sound like so many applications use it, but from my program, it showed very few use it. Am I doing something wrong, or does this truly mean that there are no interfaces with available public methods on them? The majority of the other services returned the same thing. Is it common for many services on dbus to not have any interfaces or public methods available?

2. And while I'm at it, some of the services return this:

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<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
                      "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<!-- GDBus 2.40.2 -->
<node>
</node>

why is this different, and where is it getting GDBus 2.40.2? I don't know if it's talking about Qt's QDBus, or the actual GNU dbus utility's version. I tried looking in the cli dbus manual and its help option, and I could not find its version anywhere. I wondered if Qt's QDBus software might be relying on and obtaining the version of the GNU dbus. I also looked up the version of dbus-daemon, and it was a different one, so it couldn't have obtained 2.40.2 from that.

Thanks in advance

[xenopeek]

I only occasionally work with D-Bus and I don't have an answer to your questions, but have you compared your tools' results with what d-feet (the D-Bus debugger) shows you?

[otacon14112]

I'm new to dbus and still have a lot to learn. I didn't know about d-feet. It's really useful, and it can help me out a lot. Thanks for the recommendation!