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From: Havoc Pennington <hp@pobox.com>
Date: Wed, 15 Apr 2015 13:41:10 -0400
Message-ID: <CAEntwhFkkzEYyuS7N=P=PJs=Hsizzo_k2+GgsOd562argYDecw@mail.gmail.com>
Subject: Re: [GIT PULL] kdbus for 4.1-rc1
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Borislav Petkov <bp@alien8.de>, Richard Weinberger <richard@nod.at>,
        Andy Lutomirski <luto@amacapital.net>,
        Al Viro <viro@zeniv.linux.org.uk>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
        Tom Gundersen <teg@jklm.no>, Jiri Kosina <jkosina@suse.cz>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Daniel Mack <daniel@zonque.org>,
        David Herrmann <dh.herrmann@gmail.com>,
        Djalal Harouni <tixxdz@opendz.org>
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On Wed, Apr 15, 2015 at 1:20 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> I read a bit of the documentation, but not enough. I really need to sit
> down and play with code. That's the way I learn and understand.
>

It might be useful for some of the current devs to post about the best
APIs to play with these days - my old libdbus is pretty painful,
compared to some of the newer stuff.

gdbus nicely shows a callback-based way to handle owning a service,
using a function like g_bus_own_name:

https://developer.gnome.org/gio/stable/gio-Owning-Bus-Names.html#g-bus-own-name

The callback-based approach means the library can handle
reconnection/restart on behalf of the app.

The flip side (the way you use rather than provide a service) looks similar:
 https://developer.gnome.org/gio/stable/gio-Watching-Bus-Names.html#g-bus-watch-name

Here the library can deal with complexities of a service being
restarted, the app only has to write the callbacks so they can be
called more than once (with alternating appeared/vanished handlers).

You can see in those API docs more of the ordering guarantees, in this
case on callback invocation - less for apps to screw up.

Havoc
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