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<refentry id="sd_bus_error_add_map">

<refentryinfo>

<title>sd_bus_error_add_map</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>Lennart</firstname>

<surname>Poettering</surname>

<email>lennart@poettering.net</email>

</author>

</authorgroup>

</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 &lt;systemd/sd-bus.h&gt;</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, 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>

<refsect1>

<title>Notes</title>

<para>The various error definitions described here are available

as a shared library, which can be compiled and linked to with the

<constant>libsystemd</constant> <citerefentry

project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>

file.</para>

</refsect1>

<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>