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92 lines
3.0 KiB
XML
92 lines
3.0 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY % entities SYSTEM "custom-entities.ent" >
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%entities;
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]>
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<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
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<refentry id="udev_new"
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xmlns:xi="http://www.w3.org/2001/XInclude">
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<refentryinfo>
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<title>udev_new</title>
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<productname>systemd</productname>
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</refentryinfo>
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<refmeta>
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<refentrytitle>udev_new</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>udev_new</refname>
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<refname>udev_ref</refname>
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<refname>udev_unref</refname>
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<refpurpose>Create, acquire and release a udev context object</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <libudev.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>struct udev *<function>udev_new</function></funcdef>
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<paramdef><parameter>void</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>struct udev *<function>udev_ref</function></funcdef>
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<paramdef>struct udev *<parameter>udev</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>struct udev *<function>udev_unref</function></funcdef>
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<paramdef>struct udev *<parameter>udev</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>udev_new()</function> allocates a new udev context
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object and returns a pointer to it. This object is opaque and must
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not be accessed by the caller via different means than functions
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provided by libudev. Initially, the reference count of the context
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is 1. You can acquire further references, and drop gained references
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via <function>udev_ref()</function> and
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<function>udev_unref()</function>. Once the reference count hits 0,
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the context object is destroyed and freed.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, <function>udev_new()</function> returns a pointer
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to the allocated udev context. On failure, <constant>NULL</constant>
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is returned. <function>udev_ref()</function> returns the argument
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that it was passed, unmodified. <function>udev_unref()</function>
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always returns <constant>NULL</constant>.</para>
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</refsect1>
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<refsect1>
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<title>History</title>
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<para><function>udev_new()</function>,
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<function>udev_ref()</function>, and
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<function>udev_unref()</function> were added in version 221.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para><simplelist type="inline">
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<member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
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<member><citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
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</simplelist></para>
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</refsect1>
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</refentry>
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