| <?xml version='1.0'?> <!--*-nxml-*--> |
| <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
| "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
| <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> |
| |
| <refentry id="sd_bus_message_get_type" xmlns:xi="http://www.w3.org/2001/XInclude"> |
| |
| <refentryinfo> |
| <title>sd_bus_message_get_type</title> |
| <productname>systemd</productname> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>sd_bus_message_get_type</refentrytitle> |
| <manvolnum>3</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>sd_bus_message_get_type</refname> |
| <refname>sd_bus_message_get_error</refname> |
| <refname>sd_bus_message_get_errno</refname> |
| <refname>sd_bus_message_get_creds</refname> |
| <refname>sd_bus_message_is_signal</refname> |
| <refname>sd_bus_message_is_method_call</refname> |
| <refname>sd_bus_message_is_method_error</refname> |
| |
| <refpurpose>Query bus message addressing/credentials metadata</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <funcsynopsis> |
| <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_bus_message_get_type</function></funcdef> |
| <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> |
| <paramdef>uint8_t *<parameter>type</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>sd_bus_error* <function>sd_bus_message_get_error</function></funcdef> |
| <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_bus_message_get_errno</function></funcdef> |
| <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>sd_bus_creds* <function>sd_bus_message_get_creds</function></funcdef> |
| <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_bus_message_is_signal</function></funcdef> |
| <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> |
| <paramdef>const char *<parameter>interface</parameter></paramdef> |
| <paramdef>const char *<parameter>member</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_bus_message_is_method_call</function></funcdef> |
| <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> |
| <paramdef>const char *<parameter>interface</parameter></paramdef> |
| <paramdef>const char *<parameter>member</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_bus_message_is_method_error</function></funcdef> |
| <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> |
| <paramdef>const char *<parameter>name</parameter></paramdef> |
| </funcprototype> |
| </funcsynopsis> |
| |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para><function>sd_bus_message_get_type()</function> returns the type of a message in the output |
| parameter <parameter>type</parameter>, one of <constant>SD_BUS_MESSAGE_METHOD_CALL</constant>, |
| <constant>SD_BUS_MESSAGE_METHOD_RETURN</constant>, <constant>SD_BUS_MESSAGE_METHOD_ERROR</constant>, |
| <constant>SD_BUS_MESSAGE_SIGNAL</constant>. This type is either specified as a parameter when the message |
| is created using |
| <citerefentry><refentrytitle>sd_bus_message_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| or is set automatically when the message is created using |
| <citerefentry><refentrytitle>sd_bus_message_new_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_bus_message_new_method_error</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| and similar functions.</para> |
| |
| <para><function>sd_bus_message_get_error()</function> returns the error stored in the message |
| <parameter>m</parameter>, if there is any. Otherwise, it returns <constant>NULL</constant>. |
| <function>sd_bus_message_get_errno()</function> returns the error stored in the message |
| <parameter>m</parameter> as a positive errno-style value, if there is any. Otherwise, it returns zero. |
| Errors are mapped to errno values according to the default and any additional registered error mappings. |
| See <citerefentry><refentrytitle>sd-bus-errors</refentrytitle><manvolnum>3</manvolnum></citerefentry> and |
| <citerefentry><refentrytitle>sd_bus_error_add_map</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
| </para> |
| |
| <para><function>sd_bus_message_get_creds()</function> returns the message credentials attached to the |
| message <parameter>m</parameter>. If no credentials are attached to the message, it returns |
| <constant>NULL</constant>. Ownership of the credentials instance is not transferred to the caller and |
| hence should not be freed.</para> |
| |
| <para><function>sd_bus_message_is_signal()</function> checks if message <parameter>m</parameter> is a |
| signal message. If <parameter>interface</parameter> is non-null, it also checks if the message has the |
| same interface set. If <parameter>member</parameter> is non-null, it also checks if the message has the |
| same member set. Also see |
| <citerefentry><refentrytitle>sd_bus_message_new_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
| It returns true when all checks pass.</para> |
| |
| <para><function>sd_bus_message_is_method_call()</function> checks if message <parameter>m</parameter> |
| is a method call message. If <parameter>interface</parameter> is non-null, it also checks if the message |
| has the same interface set. If <parameter>member</parameter> is non-null, it also checks if the message |
| has the same member set. Also see |
| <citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
| It returns true when all checks pass.</para> |
| |
| <para><function>sd_bus_message_is_method_error()</function> checks if message <parameter>m</parameter> |
| is an error reply message. If <parameter>name</parameter> is non-null, it also checks if the message has |
| the same error identifier set. Also see |
| <citerefentry><refentrytitle>sd_bus_message_new_method_error</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
| It returns true when all checks pass.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Return Value</title> |
| |
| <para>On success, these functions (except <function>sd_bus_message_get_error()</function> and |
| <function>sd_bus_message_get_creds()</function>) return a non-negative integer. On failure, they return a |
| negative errno-style error code. <function>sd_bus_message_get_errno()</function> always returns a |
| non-negative integer, even on failure.</para> |
| |
| <refsect2> |
| <title>Errors</title> |
| |
| <para>Returned errors may indicate the following problems:</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><constant>-EINVAL</constant></term> |
| |
| <listitem><para>The message parameter <parameter>m</parameter> or an output parameter is |
| <constant>NULL</constant>.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect2> |
| </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_message_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_bus_message_set_destination</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd-bus-errors</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_bus_error_add_map</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |