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systemd/man/sd_bus_default.xml
Filipe Brandenburger 681eb9cf2b man: generate configured paths in manpages
In particular, use /lib/systemd instead of /usr/lib/systemd in distributions
like Debian which still have not adopted a /usr merge setup.

Use XML entities from man/custom-entities.ent to replace configured paths while
doing XSLT processing of the original XML files. There was precedent of some
files (such as systemd.generator.xml) which were already using this approach.

This addresses most of the (manual) fixes from this patch:
http://anonscm.debian.org/cgit/pkg-systemd/systemd.git/tree/debian/patches/Fix-paths-in-man-pages.patch?h=experimental-220

The idea of using generic XML entities was presented here:
http://lists.freedesktop.org/archives/systemd-devel/2015-May/032240.html

This patch solves almost all the issues, with the exception of:
- Path to /bin/mount and /bin/umount.
- Generic statements about preference of /lib over /etc.

These will be handled separately by follow up patches.

Tested:
- With default configure settings, ran "make install" to two separate
  directories and compared the output to confirm they matched exactly.
- Used a set of configure flags including $CONFFLAGS from Debian:
  http://anonscm.debian.org/cgit/pkg-systemd/systemd.git/tree/debian/rules
  Installed the tree and confirmed the paths use /lib/systemd instead of
  /usr/lib/systemd and that no other unexpected differences exist.
- Confirmed that `make distcheck` still passes.
2015-05-28 19:28:19 +02:00

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<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
<!ENTITY % entities SYSTEM "custom-entities.ent" >
%entities;
]>
<!--
This file is part of systemd.
Copyright 2014 Zbigniew Jędrzejewski-Szmek
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="sd_bus_default" conditional="ENABLE_KDBUS">
<refentryinfo>
<title>sd_bus_default</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>A monkey with a typewriter</contrib>
<firstname>Zbigniew</firstname>
<surname>Jędrzejewski-Szmek</surname>
<email>zbyszek@in.waw.pl</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_default</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_default</refname>
<refname>sd_bus_default_user</refname>
<refname>sd_bus_default_system</refname>
<refname>sd_bus_open</refname>
<refname>sd_bus_open_user</refname>
<refname>sd_bus_open_system</refname>
<refname>sd_bus_open_system_remote</refname>
<refname>sd_bus_open_system_machine</refname>
<refpurpose>Acquire a connection to a system or user bus</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_default</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_default_user</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_default_system</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_open</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_open_user</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_open_system</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_open_system_remote</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
<paramdef>const char *<parameter>host</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_open_system_machine</function></funcdef>
<paramdef>sd_bus **<parameter>bus</parameter></paramdef>
<paramdef>const char *<parameter>machine</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_bus_default()</function> acquires a bus
connection object to the user bus when invoked in user context or
to the system bus otherwise. The connection object is associated
to the calling thread. Each time the function is invoked from the
same thread the same object is returned, but its reference count
increased by one, as long as at least one reference is kept. When
the last reference to the connection is dropped (using the
<function>sd_bus_unref()</function> call), the connection is
terminated. Note that the connection is not automatically
terminated when the associated thread ends. It is important to
drop the last reference to the bus connection explicitly before
the thread ends or otherwise the connection will be leaked.</para>
<para><function>sd_bus_default_user()</function> returns a user
bus connection object associated to the calling thread.
<function>sd_bus_default_system()</function> is similar, but
connects to the system bus.</para>
<para><function>sd_bus_open()</function> creates a new,
independent bus connection to the user bus when invoked in user
context or the system bus
otherwise. <function>sd_bus_open_user()</function> is similar, but
connects only to the user bus.
<function>sd_bus_open_system()</function> does the same, but
connects to the system bus. In contrast to
<function>sd_bus_default()</function>,
<function>sd_bus_default_user()</function>,
<function>sd_bus_default_system()</function> these calls return
new, independent connection objects that are not associated with
the invoking thread and are not shared between multiple
invocations. It is recommended to share connections per thread to
efficiently make use the available resources. Thus, it is
recommended to use <function>sd_bus_default()</function>,
<function>sd_bus_default_user()</function>,
<function>sd_bus_default_system()</function> to connect to the
user or system buses.</para>
<para>If the <varname>$DBUS_SESSION_BUS_ADDRESS</varname> environment
variable is set
(cf. <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>),
it will be used as the address of the user bus. This variable can
contain multiple addresses separated by <literal>;</literal>. If
this variable is not set, a suitable default for the default user
D-Bus instance will be used.</para>
<para>If the <varname>$DBUS_SYSTEM_BUS_ADDRESS</varname>
environment variable is set, it will be used as the address of the
system bus. This variable uses the same syntax as
<varname>$DBUS_SESSION_BUS_ADDRESS</varname>. If this variable is
not set, a suitable default for the default system D-Bus instance
will be used.</para>
<para><function>sd_bus_open_system_remote()</function> connects to
the system bus on the specified <parameter>host</parameter> using
SSH. <parameter>host</parameter> consists of an optional user name
followed by the <literal>@</literal> symbol, and the hostname.
</para>
<para><function>sd_bus_open_system_container()</function> connects
to the system bus in the specified <parameter>machine</parameter>,
where <parameter>machine</parameter> is the name of a local
container. See
<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
for more information about "machines".</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, these calls return 0 or a positive
integer. On failure, these calls return a negative
errno-style error code.</para>
</refsect1>
<refsect1>
<title>Reference ownership</title>
<para>The functions <function>sd_bus_open_user()</function>,
<function>sd_bus_open()</function>,
<function>sd_bus_open_system()</function>,
<function>sd_bus_open_system_remote()</function>, and
<function>sd_bus_open_system_machine()</function> return a new
object and the caller owns the sole reference. When not needed
anymore, this reference should be destroyed with
<citerefentry><refentrytitle>sd_bus_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
<para>The functions <function>sd_bus_default()</function>,
<function>sd_bus_default_user()</function> and
<function>sd_bus_default_system()</function> do not necessarily
create a new object, but increase the connection reference by
one. Use
<citerefentry><refentrytitle>sd_bus_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
to drop the reference.</para>
</refsect1>
<refsect1>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-EINVAL</constant></term>
<listitem><para>The specified parameters are invalid.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ESOCKTNOSUPPORT</constant></term>
<listitem><para>The protocol version required to connect to the selected bus is not supported.</para></listitem>
</varlistentry>
</variablelist>
<para>In addition, any further connection-related errors may be
by returned. See <citerefentry><refentrytitle>sd_bus_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para><function>sd_bus_open_user()</function> and the other
functions described here are available as a shared library, which
can be compiled and linked to with the
<constant>libsystemd</constant> <citerefentry
project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='die-net'><refentrytitle>ssh</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>