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From: Reto Buerki <reet@codelabs.ch>
Newsgroups: comp.lang.ada
Subject: Re: Announce: D_Bus/Ada, talk with your desktop in Ada
Date: Mon, 5 Dec 2011 12:12:54 +0000 (UTC)
Organization: A noiseless patient Spider
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Date: 2011-12-05T12:12:54+00:00
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On 2011-12-05, Yannick Duchêne <yannick_duchene@yahoo.fr> wrote:
> Le Mon, 05 Dec 2011 12:17:30 +0100, Reto Buerki <reet@codelabs.ch> a écrit:
>> [2] - http://www.codelabs.ch/dbus-ada
> At the bottom of the above page, in section “Examples”, there's a
>
>
>      with D_Bus.Arguments.Basic;
>      with D_Bus.Arguments.Containers;
>
> Then later
>
>      pragma Unreferenced (D_Bus.Arguments.Basic);
>      pragma Unreferenced (D_Bus.Arguments.Containers);
>
>
> Do you withed both for initialization side effects ?

No. This is needed to make the basic and container types known to the
D_Bus/Ada type system. D_Bus/Ada uses generic dispatching to create
Arguments from low-level D-Bus message arguments.

The example does not use specific argument extensions, that's why both
packages are Unreferenced.

E.g. if you remove 'with D_Bus.Arguments.Containers' in this example
you'll get:

raised D_BUS.D_BUS_ERROR : Unknown type code 'a' in message

The type system does not know how to deserialize the D-Bus ARRAY(97)
type.

- reto