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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
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Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+<?xml version='1.0'?> <!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//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-or-later -->
+
+<refentry id="udev_device_new_from_syspath"
+ xmlns:xi="http://www.w3.org/2001/XInclude">
+
+ <refentryinfo>
+ <title>udev_device_new_from_syspath</title>
+ <productname>systemd</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>udev_device_new_from_syspath</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>udev_device_new_from_syspath</refname>
+ <refname>udev_device_new_from_devnum</refname>
+ <refname>udev_device_new_from_subsystem_sysname</refname>
+ <refname>udev_device_new_from_device_id</refname>
+ <refname>udev_device_new_from_environment</refname>
+ <refname>udev_device_ref</refname>
+ <refname>udev_device_unref</refname>
+
+ <refpurpose>Create, acquire and release a udev device object</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include &lt;libudev.h&gt;</funcsynopsisinfo>
+
+ <funcprototype>
+ <funcdef>struct udev_device *<function>udev_device_new_from_syspath</function></funcdef>
+ <paramdef>struct udev *<parameter>udev</parameter></paramdef>
+ <paramdef>const char *<parameter>syspath</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>struct udev_device *<function>udev_device_new_from_devnum</function></funcdef>
+ <paramdef>struct udev *<parameter>udev</parameter></paramdef>
+ <paramdef>char <parameter>type</parameter></paramdef>
+ <paramdef>dev_t <parameter>devnum</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>struct udev_device *<function>udev_device_new_from_subsystem_sysname</function></funcdef>
+ <paramdef>struct udev *<parameter>udev</parameter></paramdef>
+ <paramdef>const char *<parameter>subsystem</parameter></paramdef>
+ <paramdef>const char *<parameter>sysname</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>struct udev_device *<function>udev_device_new_from_device_id</function></funcdef>
+ <paramdef>struct udev *<parameter>udev</parameter></paramdef>
+ <paramdef>const char *<parameter>id</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>struct udev_device *<function>udev_device_new_from_environment</function></funcdef>
+ <paramdef>struct udev *<parameter>udev</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>struct udev_device *<function>udev_device_ref</function></funcdef>
+ <paramdef>struct udev_device *<parameter>udev_device</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>struct udev_device *<function>udev_device_unref</function></funcdef>
+ <paramdef>struct udev_device *<parameter>udev_device</parameter></paramdef>
+ </funcprototype>
+
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><function>udev_device_new_from_syspath()</function>,
+ <function>udev_device_new_from_devnum()</function>,
+ <function>udev_device_new_from_subsystem_sysname()</function>,
+ <function>udev_device_new_from_device_id()</function>, and
+ <function>udev_device_new_from_environment()</function>
+ allocate a new udev device object and returns a pointer to it. This
+ object is opaque and must not be accessed by the caller via different
+ means than functions provided by libudev. Initially, the reference count
+ of the device is 1. You can acquire further references, and drop
+ gained references via <function>udev_device_ref()</function> and
+ <function>udev_device_unref()</function>. Once the reference count hits 0,
+ the device object is destroyed and freed.</para>
+
+ <para><function>udev_device_new_from_syspath()</function>,
+ <function>udev_device_new_from_devnum()</function>,
+ <function>udev_device_new_from_subsystem_sysname()</function>, and
+ <function>udev_device_new_from_device_id()</function>
+ create the device object based on information found in
+ <filename>/sys/</filename>, annotated with properties from the udev-internal
+ device database. A syspath is any subdirectory of <filename>/sys/</filename>,
+ with the restriction that a subdirectory of <filename>/sys/devices</filename>
+ (or a symlink to one) represents a real device and as such must contain
+ a <filename>uevent</filename> file. <function>udev_device_new_from_devnum()</function>
+ takes a device type, which can be <constant>b</constant> for block devices or
+ <constant>c</constant> for character devices, as well as a devnum (see
+ <citerefentry project='man-pages'><refentrytitle>makedev</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
+ <function>udev_device_new_from_subsystem_sysname()</function> looks up devices based
+ on the provided subsystem and sysname
+ (see <citerefentry><refentrytitle>udev_device_get_subsystem</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>udev_device_get_sysname</refentrytitle><manvolnum>3</manvolnum></citerefentry>)
+ and <function>udev_device_new_from_device_id()</function> looks up devices based on the provided
+ device ID, which is a special string in one of the following four forms:
+ <table>
+ <title>Device ID strings</title>
+
+ <tgroup cols='2'>
+ <colspec colname='example' />
+ <colspec colname='explanation' />
+ <thead><row>
+ <entry>Example</entry>
+ <entry>Explanation</entry>
+ </row></thead>
+ <tbody>
+ <row><entry><varname>b8:2</varname></entry>
+ <entry>block device major:minor</entry></row>
+
+ <row><entry><varname>c128:1</varname></entry>
+ <entry>char device major:minor</entry></row>
+
+ <row><entry><varname>n3</varname></entry>
+ <entry>network device ifindex</entry></row>
+
+ <row><entry><varname>+sound:card29</varname></entry>
+ <entry>kernel driver core subsystem:device name</entry></row>
+ </tbody>
+ </tgroup>
+ </table>
+ </para>
+
+ <para><function>udev_device_new_from_environment()</function>
+ creates a device from the current environment (see
+ <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>).
+ Each key-value pair is interpreted in the same way as if it was
+ received in an uevent (see
+ <citerefentry><refentrytitle>udev_monitor_receive_device</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
+ The keys <constant>DEVPATH</constant>, <constant>SUBSYSTEM</constant>,
+ <constant>ACTION</constant>, and <constant>SEQNUM</constant> are mandatory.</para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>On success, <function>udev_device_new_from_syspath()</function>,
+ <function>udev_device_new_from_devnum()</function>,
+ <function>udev_device_new_from_subsystem_sysname()</function>,
+ <function>udev_device_new_from_device_id()</function> and
+ <function>udev_device_new_from_environment()</function> return a
+ pointer to the allocated udev device. On failure,
+ <constant>NULL</constant> is returned,
+ and <varname>errno</varname> is set appropriately.
+ <function>udev_device_ref()</function> returns the argument
+ that it was passed, unmodified.
+ <function>udev_device_unref()</function> always returns
+ <constant>NULL</constant>.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>History</title>
+ <para><function>udev_device_new_from_syspath()</function>,
+ <function>udev_device_new_from_devnum()</function>,
+ <function>udev_device_new_from_subsystem_sysname()</function>,
+ <function>udev_device_new_from_device_id()</function>,
+ <function>udev_device_new_from_environment()</function>,
+ <function>udev_device_ref()</function>, and
+ <function>udev_device_unref()</function> were added in version 221.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+
+ <para>
+ <citerefentry><refentrytitle>udev_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>udev_device_get_syspath</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>udev_device_has_tag</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>,
+ </para>
+ </refsect1>
+
+</refentry>