man/udev_new.xml

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   8 <!--
   9   SPDX-License-Identifier: LGPL-2.1+
  10
  11   Copyright © 2015 David Herrmann <dh.herrmann@gmail.com>
  12 -->
  13
  14 <refentry id="udev_new"
  15   xmlns:xi="http://www.w3.org/2001/XInclude">
  16
  17   <refentryinfo>
  18     <title>udev_new</title>
  19     <productname>systemd</productname>
  20
  21     <authorgroup>
  22       <author>
  23         <contrib>Developer</contrib>
  24         <firstname>David</firstname>
  25         <surname>Herrmann</surname>
  26         <email>dh.herrmann@gmail.com</email>
  27       </author>
  28     </authorgroup>
  29   </refentryinfo>
  30
  31   <refmeta>
  32     <refentrytitle>udev_new</refentrytitle>
  33     <manvolnum>3</manvolnum>
  34   </refmeta>
  35
  36   <refnamediv>
  37     <refname>udev_new</refname>
  38     <refname>udev_ref</refname>
  39     <refname>udev_unref</refname>
  40
  41     <refpurpose>Create, acquire and release a udev context object</refpurpose>
  42   </refnamediv>
  43
  44   <refsynopsisdiv>
  45     <funcsynopsis>
  46       <funcsynopsisinfo>#include &lt;libudev.h&gt;</funcsynopsisinfo>
  47
  48       <funcprototype>
  49         <funcdef>struct udev *<function>udev_new</function></funcdef>
  50         <paramdef><parameter>void</parameter></paramdef>
  51       </funcprototype>
  52
  53       <funcprototype>
  54         <funcdef>struct udev *<function>udev_ref</function></funcdef>
  55         <paramdef>struct udev *<parameter>udev</parameter></paramdef>
  56       </funcprototype>
  57
  58       <funcprototype>
  59         <funcdef>struct udev *<function>udev_unref</function></funcdef>
  60         <paramdef>struct udev *<parameter>udev</parameter></paramdef>
  61       </funcprototype>
  62
  63     </funcsynopsis>
  64   </refsynopsisdiv>
  65
  66   <refsect1>
  67     <title>Description</title>
  68
  69     <para><function>udev_new()</function> allocates a new udev context
  70     object and returns a pointer to it. This object is opaque and must
  71     not be accessed by the caller via different means than functions
  72     provided by libudev. Initially, the reference count of the context
  73     is 1. You can acquire further references, and drop gained references
  74     via <function>udev_ref()</function> and
  75     <function>udev_unref()</function>. Once the reference count hits 0,
  76     the context object is destroyed and freed.</para>
  77   </refsect1>
  78
  79   <refsect1>
  80     <title>Return Value</title>
  81
  82     <para>On success, <function>udev_new()</function> returns a pointer
  83     to the allocated udev context. On failure, <constant>NULL</constant>
  84     is returned. <function>udev_ref()</function> returns the argument
  85     that it was passed, unmodified. <function>udev_unref()</function>
  86     always returns <constant>NULL</constant>.</para>
  87   </refsect1>
  88
  89   <refsect1>
  90     <title>See Also</title>
  91
  92     <para>
  93       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  94     </para>
  95   </refsect1>
  96
  97 </refentry>