diff options
Diffstat (limited to 'man/sd_bus_default.xml')
| -rw-r--r-- | man/sd_bus_default.xml | 312 |
1 files changed, 0 insertions, 312 deletions
diff --git a/man/sd_bus_default.xml b/man/sd_bus_default.xml deleted file mode 100644 index 6d5a90de72..0000000000 --- a/man/sd_bus_default.xml +++ /dev/null @@ -1,312 +0,0 @@ -<?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"> - -<!-- - 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"> - - <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 <systemd/sd-bus.h></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 - with the calling thread. Each time the function is invoked from - the same thread, the same object is returned, but its reference - count is increased by one, as long as at least one reference is - kept. When the last reference to the connection is dropped (using - the - <citerefentry><refentrytitle>sd_bus_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> - 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, as otherwise, the connection will - leak. Also, queued but unread or unwritten messages keep the - bus referenced, see below.</para> - - <para><function>sd_bus_default_user()</function> returns a user - bus connection object associated with the calling thread. - <function>sd_bus_default_system()</function> is similar, but - connects to the system bus. Note that - <function>sd_bus_default()</function> is identical to these two - calls, depending on the execution context.</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>, and - <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> and - <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 - <citerefentry - project='die-net'><refentrytitle>ssh</refentrytitle><manvolnum>1</manvolnum></citerefentry>. <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_machine()</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 the "machine" concept. Note that - connections into local containers are only available to privileged - processes at this time.</para> - - <para>These calls allocate a bus connection object and initiate - the connection to a well-known bus of some form. An alternative to - using these high-level calls is to create an unconnected bus - object with - <citerefentry><refentrytitle>sd_bus_new</refentrytitle><manvolnum>3</manvolnum></citerefentry> - and to connect it with - <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>. - </para> - - </refsect1> - - <refsect1> - <title>Reference ownership</title> - <para>The functions <function>sd_bus_open()</function>, - <function>sd_bus_open_user()</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 - connection 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 of an - existing connection object by one. Use - <citerefentry><refentrytitle>sd_bus_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> - to drop the reference.</para> - - <para>Queued but unwritten/unread messages also keep a reference - to their bus connection object. For this reason, even if an - application dropped all references to a bus connection, it might - not get destroyed right away. Until all incoming queued - messages are read, and until all outgoing unwritten messages are - written, the bus object will stay - alive. <function>sd_bus_flush()</function> may be used to write - all outgoing queued messages so they drop their references. To - flush the unread incoming messages, use - <function>sd_bus_close()</function>, which will also close the bus - connection. When using the default bus logic, it is a good idea to - first invoke <function>sd_bus_flush()</function> followed by - <function>sd_bus_close()</function> when a thread or process - terminates, and thus its bus connection object should be - freed.</para> - - <para>The life cycle of the default bus connection should be the - responsibility of the code that creates/owns the thread the - default bus connection object is associated with. Library code - should neither call <function>sd_bus_flush()</function> nor - <function>sd_bus_close()</function> on default bus objects unless - it does so in its own private, self-allocated thread. Library code - should not use the default bus object in other threads unless it - is clear that the program using it will life cycle the bus - connection object and flush and close it before exiting from the - thread. In libraries where it is not clear that the calling - program will life cycle the bus connection object, it is hence - recommended to use <function>sd_bus_open_system()</function> - instead of <function>sd_bus_default_system()</function> and - related calls.</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>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> |