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This part of the copyright blurb stems from the GPL use recommendations: https://www.gnu.org/licenses/gpl-howto.en.html The concept appears to originate in times where version control was per file, instead of per tree, and was a way to glue the files together. Ultimately, we nowadays don't live in that world anymore, and this information is entirely useless anyway, as people are very welcome to copy these files into any projects they like, and they shouldn't have to change bits that are part of our copyright header for that. hence, let's just get rid of this old cruft, and shorten our codebase a bit.
123 lines
4.6 KiB
XML
123 lines
4.6 KiB
XML
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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SPDX-License-Identifier: LGPL-2.1+
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Copyright 2017 Lennart Poettering
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-->
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<refentry id="sd_bus_is_open">
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<refentryinfo>
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<title>sd_bus_is_open</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_bus_is_open</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_bus_is_open</refname>
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<refname>sd_bus_is_ready</refname>
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<refpurpose>Check whether the a bus connection is open or ready.</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_bus_is_open</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_bus_is_ready</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_bus_is_open()</function> checks whether the specified bus connection is open, i.e. in the
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process of being established, already established or in the process of being torn down. It returns zero when the
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connection has not been started yet
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(i.e. <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry> or some
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equivalent call has not been invoked yet), or is fully terminated again (for example after
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<citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>), it returns
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positive otherwise.</para>
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<para><function>sd_bus_is_ready()</function> checks whether the specified connection is fully established,
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i.e. completed the connection and authentication phases of the protocol and received the
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<function>Hello()</function> method call response, and is not in the process of being torn down again. It returns
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zero outside of this state, and positive otherwise. Effectively, this function returns positive while regular
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messages can be sent or received on the connection.</para>
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<para>To be notified when the connection is fully established, use
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<citerefentry><refentrytitle>sd_bus_set_connected_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry> and
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install a match for the <function>Connected()</function> signal on the
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<literal>org.freedesktop.DBus.Local</literal> interface. To be notified when the connection is torn down again,
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install a match for the <function>Disconnected()</function> signal on the
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<literal>org.freedesktop.DBus.Local</literal> interface.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style
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error code.</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-ECHILD</constant></term>
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<listitem><para>The bus connection has been created in a different process.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para><function>sd_bus_is_open()</function> and <function>sd_bus_is_ready()</function> are available as
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a shared library, which can be compiled and linked to with the <constant>libsystemd</constant> <citerefentry
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project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_set_connected_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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