man/sd_hwdb_new.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="sd_hwdb_new" xmlns:xi="http://www.w3.org/2001/XInclude">
   7   <refentryinfo>
   8     <title>sd_hwdb_new</title>
   9     <productname>systemd</productname>
  10   </refentryinfo>
  11
  12   <refmeta>
  13     <refentrytitle>sd_hwdb_new</refentrytitle>
  14     <manvolnum>3</manvolnum>
  15   </refmeta>
  16
  17   <refnamediv>
  18     <refname>sd_hwdb_new</refname>
  19     <refname>sd_hwdb_new_from_path</refname>
  20     <refname>sd_hwdb_ref</refname>
  21     <refname>sd_hwdb_unref</refname>
  22
  23     <refpurpose>Create a new hwdb object and create or destroy references to it</refpurpose>
  24   </refnamediv>
  25
  26   <refsynopsisdiv>
  27     <funcsynopsis>
  28       <funcsynopsisinfo>#include &lt;systemd/sd-hwdb.h&gt;</funcsynopsisinfo>
  29
  30       <funcprototype>
  31         <funcdef>int <function>sd_hwdb_new</function></funcdef>
  32         <paramdef>sd_hwdb **<parameter>hwdb</parameter></paramdef>
  33       </funcprototype>
  34
  35       <funcprototype>
  36         <funcdef>int <function>sd_hwdb_new_from_path</function></funcdef>
  37         <paramdef>const char *<parameter>path</parameter></paramdef>
  38         <paramdef>sd_hwdb **<parameter>hwdb</parameter></paramdef>
  39       </funcprototype>
  40
  41       <funcprototype>
  42         <funcdef>sd_hwdb* <function>sd_hwdb_ref</function></funcdef>
  43         <paramdef>sd_hwdb *<parameter>hwdb</parameter></paramdef>
  44       </funcprototype>
  45
  46       <funcprototype>
  47         <funcdef>sd_hwdb* <function>sd_hwdb_unref</function></funcdef>
  48         <paramdef>sd_hwdb *<parameter>hwdb</parameter></paramdef>
  49       </funcprototype>
  50     </funcsynopsis>
  51   </refsynopsisdiv>
  52
  53   <refsect1>
  54     <title>Description</title>
  55
  56     <para><function>sd_hwdb_new()</function> creates a new hwdb object to access the binary hwdb
  57     database. Upon initialization, the file containing the binary representation of the hardware database is
  58     located and opened. The new object is returned in <parameter>hwdb</parameter>.</para>
  59
  60     <para><function>sd_hwdb_new_from_path()</function> may be used to specify the path from which the binary
  61     hardware database should be opened.</para>
  62
  63     <para>The <parameter>hwdb</parameter> object is reference counted. <function>sd_hwdb_ref()</function> and
  64     <function>sd_hwdb_unref()</function> may be used to get a new reference or destroy an existing reference
  65     to an object. The caller must dispose of the reference acquired with <function>sd_hwdb_new()</function>
  66     by calling <function>sd_hwdb_unref()</function> when done with the object.</para>
  67
  68     <para>Use
  69     <citerefentry><refentrytitle>sd_hwdb_seek</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  70     <citerefentry><refentrytitle>sd_hwdb_get</refentrytitle><manvolnum>3</manvolnum></citerefentry>, and
  71     <citerefentry><refentrytitle>sd_hwdb_enumerate</refentrytitle><manvolnum>3</manvolnum></citerefentry> to
  72     access entries.</para>
  73   </refsect1>
  74
  75   <refsect1>
  76     <title>Return Value</title>
  77
  78     <para>On success, <function>sd_hwdb_new()</function> and <function>sd_hwdb_new_from_path()</function>
  79     return a non-negative integer. On failure, a negative errno-style error code is returned.</para>
  80
  81     <para><function>sd_hwdb_ref()</function> always returns the argument.
  82     </para>
  83
  84     <para><function>sd_hwdb_unref()</function> always returns <constant>NULL</constant>.
  85     </para>
  86
  87     <refsect2>
  88       <title>Errors</title>
  89
  90       <para>Returned errors may indicate the following problems:</para>
  91
  92       <variablelist>
  93         <varlistentry>
  94           <term><constant>-ENOENT</constant></term>
  95
  96           <listitem><para>The binary hardware database file could not be located. See
  97           <citerefentry><refentrytitle>systemd-hwdb</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  98           for more information.</para>
  99
 100           <xi:include href="version-info.xml" xpointer="v246"/>
 101           </listitem>
 102         </varlistentry>
 103
 104         <varlistentry>
 105           <term><constant>-EINVAL</constant></term>
 106
 107           <listitem><para>The located binary hardware database file is in an incompatible format.
 108           </para>
 109
 110           <xi:include href="version-info.xml" xpointer="v246"/></listitem>
 111         </varlistentry>
 112
 113         <varlistentry>
 114           <term><constant>-ENOMEM</constant></term>
 115
 116           <listitem><para>Memory allocation failed.</para>
 117
 118           <xi:include href="version-info.xml" xpointer="v246"/></listitem>
 119         </varlistentry>
 120       </variablelist>
 121     </refsect2>
 122   </refsect1>
 123
 124   <xi:include href="libsystemd-pkgconfig.xml" />
 125
 126   <refsect1>
 127     <title>History</title>
 128     <para><function>sd_hwdb_new()</function> was added in version 246.</para>
 129     <para><function>sd_hwdb_ref()</function> was added in version 246.</para>
 130     <para><function>sd_hwdb_unref()</function> was added in version 246.</para>
 131     <para><function>sd_hwdb_new_from_path()</function> was added in version 252.</para>
 132   </refsect1>
 133
 134   <refsect1>
 135     <title>See Also</title>
 136
 137     <para>
 138       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 139       <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 140       <citerefentry><refentrytitle>sd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 141       <citerefentry><refentrytitle>systemd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 142     </para>
 143   </refsect1>
 144
 145 </refentry>