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systemd-stable/man/libudev.xml
Lennart Poettering 64a7ef8bc0 man: be more explicit about thread safety of sd_journal
Triggered by https://bugzilla.redhat.com/show_bug.cgi?id=1609349

This adds two generic paragaphs we include via xinclude. One is the
"strict" version, which contains wording saying that we are thread
agnostic and what that means. And the other is the "safe" version, for
the cases we provide fully safety.

Let's then change most man pages to use either of these generic
paragraphs. With one exception: man/sd_journal_get_catalog.xml contains
both kinds of function, we hence use manual wording.
2018-08-03 17:36:11 +02:00

100 lines
4.1 KiB
XML

<?xml version='1.0'?> <!--*-nxml-*-->
<!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;
]>
<!--
SPDX-License-Identifier: LGPL-2.1+
-->
<refentry id="libudev"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>libudev</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>libudev</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>libudev</refname>
<refpurpose>API for enumerating and introspecting local devices</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;libudev.h&gt;</funcsynopsisinfo>
</funcsynopsis>
<cmdsynopsis>
<command>pkg-config --cflags --libs libudev</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><filename>libudev.h</filename> provides APIs to introspect
and enumerate devices on the local system.</para>
<para>All functions require a libudev context to operate. This
context can be create via
<citerefentry><refentrytitle>udev_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
It is used to track library state and link objects together. No
global state is used by libudev, everything is always linked to
a udev context.</para>
<xi:include href="threads-aware.xml" xpointer="strict"/>
<para>To introspect a local device on a system, a udev device
object can be created via
<citerefentry><refentrytitle>udev_device_new_from_syspath</refentrytitle><manvolnum>3</manvolnum></citerefentry>
and friends. The device object allows one to query current state,
read and write attributes and lookup properties of the device in
question.</para>
<para>To enumerate local devices on the system, an enumeration
object can be created via
<citerefentry><refentrytitle>udev_enumerate_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
<para>To monitor the local system for hotplugged or unplugged
devices, a monitor can be created via
<citerefentry><refentrytitle>udev_monitor_new_from_netlink</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
<para>Whenever libudev returns a list of objects, the
<citerefentry><refentrytitle>udev_list_entry</refentrytitle><manvolnum>3</manvolnum></citerefentry>
API should be used to iterate, access and modify those lists.</para>
<para>Furthermore, libudev also exports legacy APIs that should
not be used by new software (and as such are not documented as
part of this manual). This includes the hardware database known
as <constant>udev_hwdb</constant> (please use the new
<citerefentry><refentrytitle>sd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry>
API instead) and the <constant>udev_queue</constant> object to
query the udev daemon (which should not be used by new software
at all).</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>udev_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>udev_device_new_from_syspath</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>udev_enumerate_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>udev_monitor_new_from_netlink</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>udev_list_entry</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-device</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>