man/sd_bus_error_add_map.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+ -->
   5
   6 <refentry id="sd_bus_error_add_map"
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>sd_bus_error_add_map</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>sd_bus_error_add_map</refentrytitle>
  16     <manvolnum>3</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>sd_bus_error_add_map</refname>
  21     <refname>sd_bus_error_map</refname>
  22     <refname>SD_BUS_ERROR_MAP</refname>
  23     <refname>SD_BUS_ERROR_END</refname>
  24
  25     <refpurpose>Additional sd-dbus error mappings</refpurpose>
  26   </refnamediv>
  27
  28   <refsynopsisdiv>
  29     <funcsynopsis>
  30       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  31
  32       <funcsynopsisinfo>typedef struct {
  33         const char *name;
  34         int code;
  35         …
  36 } sd_bus_error_map;</funcsynopsisinfo>
  37
  38     </funcsynopsis>
  39
  40       <para>
  41         <constant>SD_BUS_ERROR_MAP(<replaceable>name</replaceable>, <replaceable>code</replaceable>)</constant>
  42       </para>
  43       <para>
  44         <constant>SD_BUS_ERROR_MAP_END</constant>
  45       </para>
  46
  47       <funcprototype>
  48         <funcdef>int <function>sd_bus_error_add_map</function></funcdef>
  49         <paramdef>const sd_bus_map *<parameter>map</parameter></paramdef>
  50       </funcprototype>
  51
  52   </refsynopsisdiv>
  53
  54   <refsect1>
  55     <title>Description</title>
  56
  57     <para>The <function>sd_bus_error_add_map()</function> call may be
  58     used to register additional mappings for converting D-Bus errors
  59     to Linux <varname>errno</varname>-style errors. The mappings
  60     defined with this call are consulted by calls such as
  61     <citerefentry><refentrytitle>sd_bus_error_set</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  62     or
  63     <citerefentry><refentrytitle>sd_bus_error_get_errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>. By
  64     default, a number of generic, standardized mappings are known, as
  65     documented in
  66     <citerefentry><refentrytitle>sd-bus-errors</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Use
  67     this call to add further, application-specific mappings.</para>
  68
  69     <para>The function takes a pointer to an array of
  70     <structname>sd_bus_error_map</structname> structures. A reference
  71     to the specified array is added to the lookup tables for error
  72     mappings. Note that the structure is not copied, and that it is hence
  73     essential that the array stays available and constant during the
  74     entire remaining runtime of the process.</para>
  75
  76     <para>The mapping array should be put together with a series of
  77     <constant>SD_BUS_ERROR_MAP()</constant> macro invocations that
  78     take a literal name string and a (positive)
  79     <varname>errno</varname>-style error number. The last entry of the
  80     array should be an invocation of the
  81     <constant>SD_BUS_ERROR_MAP_END</constant> macro. The array should not be
  82     put together without use of these two macros.</para>
  83
  84     <para>Note that the call is idempotent: it is safe to invoke it
  85     multiple times with the parameter, which will only add the passed
  86     mapping array once.</para>
  87
  88     <para>Note that the memory allocated by this call is not intended
  89     to be freed during the lifetime of the process. It should not be
  90     freed explicitly.</para>
  91   </refsect1>
  92
  93   <refsect1>
  94     <title>Return Value</title>
  95
  96     <para><function>sd_bus_error_add_map()</function> returns a
  97     positive value when the new array was added to the lookup
  98     tables. It returns zero when the same array was already added
  99     before. On error, a negative <varname>errno</varname>-style error
 100     code is returned. See below for known error codes.</para>
 101
 102     <refsect2>
 103       <title>Errors</title>
 104
 105       <para>Returned errors may indicate the following problems:</para>
 106
 107       <variablelist>
 108
 109         <varlistentry>
 110           <term><constant>-EINVAL</constant></term>
 111
 112           <listitem><para>The specified mapping array is invalid.</para></listitem>
 113         </varlistentry>
 114
 115         <varlistentry>
 116           <term><constant>-ENOMEM</constant></term>
 117
 118           <listitem><para>Memory allocation failed.</para></listitem>
 119         </varlistentry>
 120       </variablelist>
 121     </refsect2>
 122   </refsect1>
 123
 124   <xi:include href="libsystemd-pkgconfig.xml" />
 125
 126   <refsect1>
 127     <title>See Also</title>
 128
 129     <para>
 130       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 131       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 132       <citerefentry><refentrytitle>sd_bus_error</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 133       <citerefentry><refentrytitle>sd-bus-errors</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 134       <citerefentry project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 135       <citerefentry project='die-net'><refentrytitle>strerror_r</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 136     </para>
 137   </refsect1>
 138
 139 </refentry>