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mirror of https://github.com/systemd/systemd.git synced 2024-12-22 17:35:35 +03:00
systemd/man/sd_bus_message_new_signal.xml
Štěpán Němec 597c6cc119 man: fix incorrect volume numbers in internal man page references
Some ambiguity (e.g., same-named man pages in multiple volumes)
makes it impossible to fully automate this, but the following
Python snippet (run inside the man/ directory of the systemd repo)
helped to generate the sed command lines (which were subsequently
manually reviewed, run and the false positives reverted):

from pathlib import Path

import lxml
from lxml import etree as ET

man2vol: dict[str, str] = {}
man2citerefs: dict[str, list] = {}

for file in Path(".").glob("*.xml"):
    tree = ET.parse(file, lxml.etree.XMLParser(recover=True))
    meta = tree.find("refmeta")
    if meta is not None:
        title = meta.findtext("refentrytitle")
        if title is not None:
            vol = meta.findtext("manvolnum")
            if vol is not None:
                man2vol[title] = vol
            citerefs = list(tree.iter("citerefentry"))
            if citerefs:
                man2citerefs[title] = citerefs

for man, refs in man2citerefs.items():
    for ref in refs:
        title = ref.findtext("refentrytitle")
        if title is not None:
            has = ref.findtext("manvolnum")
            try:
                should_have = man2vol[title]
            except KeyError:  # Non-systemd man page reference?  Ignore.
                continue
            if has != should_have:
                print(
                    f"sed -i '\\|<citerefentry><refentrytitle>{title}"
                    f"</refentrytitle><manvolnum>{has}</manvolnum>"
                    f"</citerefentry>|s|<manvolnum>{has}</manvolnum>|"
                    f"<manvolnum>{should_have}</manvolnum>|' {man}.xml"
                )
2024-11-11 20:31:08 +01:00

140 lines
5.4 KiB
XML

<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="sd_bus_message_new_signal"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_message_new_signal</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_message_new_signal</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_message_new_signal</refname>
<refname>sd_bus_message_new_signal_to</refname>
<refpurpose>Create a signal message</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int sd_bus_message_new_signal</funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>sd_bus_message **<parameter>m</parameter></paramdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
<paramdef>const char *<parameter>interface</parameter></paramdef>
<paramdef>const char *<parameter>member</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int sd_bus_message_new_signal_to</funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>sd_bus_message **<parameter>m</parameter></paramdef>
<paramdef>const char *<parameter>destination</parameter></paramdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
<paramdef>const char *<parameter>interface</parameter></paramdef>
<paramdef>const char *<parameter>member</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>The <function>sd_bus_message_new_signal()</function> function creates a new bus message
object that encapsulates a D-Bus signal, and returns it in the <parameter>m</parameter> output
parameter. The signal will be sent to path <parameter>path</parameter>, on the interface
<parameter>interface</parameter>, member <parameter>member</parameter>. When this message is
sent, no reply is expected. See
<citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for a short description of the meaning of the <parameter>path</parameter>,
<parameter>interface</parameter>, and <parameter>member</parameter> parameters.
</para>
<para><function>sd_bus_message_new_signal_to()</function> is a shorthand for creating a new bus message
to a specific destination. It's behavior is similar to calling
<function>sd_bus_message_new_signal()</function> followed by calling
<citerefentry><refentrytitle>sd_bus_message_set_destination</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>This function returns 0 if the message object was successfully created, and a negative
errno-style error code otherwise.</para>
<refsect2>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-EINVAL</constant></term>
<listitem><para>The output parameter <parameter>m</parameter> is
<constant>NULL</constant>.</para>
<para>The <parameter>path</parameter> parameter is not a valid D-Bus path
(<literal>/an/object/path</literal>), the <parameter>interface</parameter> parameter is not
a valid D-Bus interface name (<literal>an.interface.name</literal>), or the
<parameter>member</parameter> parameter is not a valid D-Bus member
(<literal>Name</literal>).</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOTCONN</constant></term>
<listitem><para>The bus parameter <parameter>bus</parameter> is <constant>NULL</constant> or
the bus is not connected.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>Examples</title>
<example>
<title>Send a simple signal</title>
<programlisting><xi:include href="send-unit-files-changed.c" parse="text" /></programlisting>
<para>This function in systemd sources is used to emit the
<literal>UnitFilesChanged</literal> signal when the unit files have been changed.
</para>
</example>
</refsect1>
<refsect1>
<title>See Also</title>
<para><simplelist type="inline">
<member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_bus_emit_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_bus_message_set_destination</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
</simplelist></para>
</refsect1>
</refentry>