man/udev_new.xml

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