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<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
SPDX-License-Identifier: LGPL-2.1+
-->
<refentry id="sd_bus_error_add_map"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_error_add_map</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_error_add_map</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_error_add_map</refname>
<refname>sd_bus_error_map</refname>
<refname>SD_BUS_ERROR_MAP</refname>
<refname>SD_BUS_ERROR_END</refname>
<refpurpose>Additional sd-dbus error mappings</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
<funcsynopsisinfo>typedef struct {
const char *name;
int code;
…
} sd_bus_error_map;</funcsynopsisinfo>
</funcsynopsis>
<para>
<constant>SD_BUS_ERROR_MAP(<replaceable>name</replaceable>, <replaceable>code</replaceable>)</constant>
</para>
<para>
<constant>SD_BUS_ERROR_MAP_END</constant>
</para>
<funcprototype>
<funcdef>int <function>sd_bus_error_add_map</function></funcdef>
<paramdef>const sd_bus_map *<parameter>map</parameter></paramdef>
</funcprototype>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>The <function>sd_bus_error_add_map()</function> call may be
used to register additional mappings for converting D-Bus errors
to Linux <varname>errno</varname>-style errors. The mappings
defined with this call are consulted by calls such as
<citerefentry><refentrytitle>sd_bus_error_set</refentrytitle><manvolnum>3</manvolnum></citerefentry>
or
<citerefentry><refentrytitle>sd_bus_error_get_errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>. By
default, a number of generic, standardized mappings are known, as
documented in
<citerefentry><refentrytitle>sd-bus-errors</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Use
this call to add further, application-specific mappings.</para>
<para>The function takes a pointer to an array of
<structname>sd_bus_error_map</structname> structures. A reference
to the specified array is added to the lookup tables for error
mappings. Note that the structure is not copied, and that it is hence
essential that the array stays available and constant during the
entire remaining runtime of the process.</para>
<para>The mapping array should be put together with a series of
<constant>SD_BUS_ERROR_MAP()</constant> macro invocations that
take a literal name string and a (positive)
<varname>errno</varname>-style error number. The last entry of the
array should be an invocation of the
<constant>SD_BUS_ERROR_MAP_END</constant> macro. The array should not be
put together without use of these two macros.</para>
<para>Note that the call is idempotent: it is safe to invoke it
multiple times with the parameter, which will only add the passed
mapping array once.</para>
<para>Note that the memory allocated by this call is not intended
to be freed during the lifetime of the process. It should not be
freed explicitly.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>sd_bus_error_add_map()</function> returns a
positive value when the new array was added to the lookup
tables. It returns zero when the same array was already added
before. On error, a negative <varname>errno</varname>-style error
code is returned. See below for known error codes.</para>
</refsect1>
<refsect1>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-EINVAL</constant></term>
<listitem><para>The specified mapping array is invalid.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_error</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus-errors</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='die-net'><refentrytitle>strerror_r</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
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