Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 138 insertions, 0 deletions

diff --git a/man/sd_bus_process.xml b/man/sd_bus_process.xml
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+<?xml version='1.0'?>
+<!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
+
+  Copyright © 2016 Julian Orth
+-->
+
+<refentry id="sd_bus_process" xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <refentryinfo>
+    <title>sd_bus_process</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>sd_bus_process</refentrytitle>
+    <manvolnum>3</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>sd_bus_process</refname>
+
+    <refpurpose>Drive the connection</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
+
+      <funcprototype>
+        <funcdef>int <function>sd_bus_process</function></funcdef>
+        <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+        <paramdef>sd_bus_message **<parameter>ret</parameter></paramdef>
+      </funcprototype>
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><function>sd_bus_process()</function> drives the connection between the client and the message bus.
+    That is, it handles connecting, authentication, and processing of messages. When invoked, pending I/O
+    work is executed, and queued incoming messages are dispatched to registered callbacks. Each time it is
+    invoked a single operation is executed. It returns zero when no operations were pending and positive if a
+    message was processed. When zero is returned the caller should poll for I/O events before calling into
+    <function>sd_bus_process()</function> again. For that either use the simple, blocking
+    <citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry> call, or
+    hook up the bus connection object to an external or manual event loop using
+    <citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+    </para>
+
+    <para><function>sd_bus_process()</function> processes at most one incoming message per call.  If the parameter
+    <parameter>ret</parameter> is not <constant>NULL</constant> and the call processed a message,
+    <parameter>*ret</parameter> is set to this message.  The caller owns a reference to this message and should call
+    <citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> when the
+    message is no longer needed. If <parameter>ret</parameter> is not <constant>NULL</constant>, progress was made, but no message was
+    processed, <parameter>*ret</parameter> is set to <constant>NULL</constant>.</para>
+
+    <para>If the bus object is connected to an
+    <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> event loop (with
+    <citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>), it is not
+    necessary to call <function>sd_bus_process()</function> directly as it is invoked automatically when
+    necessary.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return Value</title>
+
+    <para>If progress was made, a positive integer is returned. If no progress was made, 0 is returned. If an
+    error occurs, a negative <varname>errno</varname>-style error code is returned.</para>
+
+    <refsect2>
+      <title>Errors</title>
+
+      <para>Returned errors may indicate the following problems:</para>
+
+      <variablelist>
+        <varlistentry>
+          <term><constant>-EINVAL</constant></term>
+
+          <listitem><para>An invalid bus object was passed.</para></listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><constant>-ECHILD</constant></term>
+
+          <listitem><para>The bus connection was allocated in a parent process and is being reused in a child
+          process after <function>fork()</function>.</para></listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><constant>-ENOTCONN</constant></term>
+
+          <listitem><para>The bus connection has been terminated already.</para></listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><constant>-ECONNRESET</constant></term>
+
+          <listitem><para>The bus connection has been terminated just now.</para></listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><constant>-EBUSY</constant></term>
+
+          <listitem><para>This function is already being called, i.e. <function>sd_bus_process()</function>
+          has been called from a callback function that itself was called by
+          <function>sd_bus_process()</function>.</para></listitem>
+        </varlistentry>
+      </variablelist>
+    </refsect2>
+  </refsect1>
+
+  <xi:include href="libsystemd-pkgconfig.xml" />
+
+  <refsect1>
+    <title>History</title>
+    <para><function>sd_bus_process()</function> was added in version 231.</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_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>