<?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; ]> <!-- This file is part of systemd. Copyright 2015 David Herrmann <dh.herrmann@gmail.com> 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="udev_new" xmlns:xi="http://www.w3.org/2001/XInclude"> <refentryinfo> <title>udev_new</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>David</firstname> <surname>Herrmann</surname> <email>dh.herrmann@gmail.com</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>udev_new</refentrytitle> <manvolnum>3</manvolnum> </refmeta> <refnamediv> <refname>udev_new</refname> <refname>udev_ref</refname> <refname>udev_unref</refname> <refpurpose>Create, acquire and release a udev context object</refpurpose> </refnamediv> <refsynopsisdiv> <funcsynopsis> <funcsynopsisinfo>#include <libudev.h></funcsynopsisinfo> <funcprototype> <funcdef>struct udev *<function>udev_new</function></funcdef> <paramdef><parameter>void</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>struct udev *<function>udev_ref</function></funcdef> <paramdef>struct udev *<parameter>udev</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>struct udev *<function>udev_unref</function></funcdef> <paramdef>struct udev *<parameter>udev</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsect1> <title>Description</title> <para><function>udev_new()</function> allocates a new udev context 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 context is 1. You can acquire further references, and drop gained references via <function>udev_ref()</function> and <function>udev_unref()</function>. Once the reference count hits 0, the context object is destroyed and freed.</para> </refsect1> <refsect1> <title>Return Value</title> <para>On success, <function>udev_new()</function> returns a pointer to the allocated udev context. On failure, <constant>NULL</constant> is returned. <function>udev_ref()</function> returns the argument that it was passed, unmodified. <function>udev_unref()</function> always returns <constant>NULL</constant>.</para> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, </para> </refsect1> </refentry>