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diff --git a/man/sd_event_wait.xml b/man/sd_event_wait.xml deleted file mode 100644 index 26327dc688..0000000000 --- a/man/sd_event_wait.xml +++ /dev/null @@ -1,356 +0,0 @@ -<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> -<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" -"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> - -<!-- - This file is part of systemd. - - Copyright 2015 Zbigniew Jędrzejewski-Szmek - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. ---> - -<refentry id="sd_event_wait" xmlns:xi="http://www.w3.org/2001/XInclude"> - - <refentryinfo> - <title>sd_event_wait</title> - <productname>systemd</productname> - - <authorgroup> - <author> - <contrib>Developer</contrib> - <firstname>Tom</firstname> - <surname>Gundersen</surname> - <email>teg@jklm.no</email> - </author> - </authorgroup> - </refentryinfo> - - <refmeta> - <refentrytitle>sd_event_wait</refentrytitle> - <manvolnum>3</manvolnum> - </refmeta> - - <refnamediv> - <refname>sd_event_wait</refname> - <refname>sd_event_prepare</refname> - <refname>sd_event_dispatch</refname> - <refname>sd_event_get_state</refname> - <refname>sd_event_get_iteration</refname> - <refname>SD_EVENT_INITIAL</refname> - <refname>SD_EVENT_PREPARING</refname> - <refname>SD_EVENT_ARMED</refname> - <refname>SD_EVENT_PENDING</refname> - <refname>SD_EVENT_RUNNING</refname> - <refname>SD_EVENT_EXITING</refname> - <refname>SD_EVENT_FINISHED</refname> - - <refpurpose>Low-level event loop operations</refpurpose> - </refnamediv> - - <refsynopsisdiv> - <funcsynopsis> - <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> - - <funcsynopsisinfo><token>enum</token> { - <constant>SD_EVENT_INITIAL</constant>, - <constant>SD_EVENT_PREPARING</constant>, - <constant>SD_EVENT_ARMED</constant>, - <constant>SD_EVENT_PENDING</constant>, - <constant>SD_EVENT_RUNNING</constant>, - <constant>SD_EVENT_EXITING</constant>, - <constant>SD_EVENT_FINISHED</constant>, -};</funcsynopsisinfo> - - <funcprototype> - <funcdef>int <function>sd_event_prepare</function></funcdef> - <paramdef>sd_event *<parameter>event</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_event_wait</function></funcdef> - <paramdef>sd_event *<parameter>event</parameter></paramdef> - <paramdef>uint64_t <parameter>usec</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_event_dispatch</function></funcdef> - <paramdef>sd_event *<parameter>event</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_event_get_state</function></funcdef> - <paramdef>sd_event *<parameter>event</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_event_get_iteration</function></funcdef> - <paramdef>sd_event *<parameter>event</parameter></paramdef> - <paramdef>uint64_t *<parameter>ret</parameter></paramdef> - </funcprototype> - - </funcsynopsis> - </refsynopsisdiv> - - <refsect1> - <title>Description</title> - - <para>The low-level <function>sd_event_prepare()</function>, - <function>sd_event_wait()</function> and - <function>sd_event_dispatch()</function> functions may be used to - execute specific phases of an event loop. See - <citerefentry><refentrytitle>sd_event_run</refentrytitle><manvolnum>3</manvolnum></citerefentry> - and - <citerefentry><refentrytitle>sd_event_loop</refentrytitle><manvolnum>3</manvolnum></citerefentry> - for higher-level functions that execute individual but complete - iterations of an event loop or run it continuously.</para> - - <para><function>sd_event_prepare()</function> checks for pending - events and arms necessary timers. If any events are ready to be - processed ("pending"), it returns a positive, non-zero value, and the caller - should process these events with - <function>sd_event_dispatch()</function>.</para> - - <para><function>sd_event_dispatch()</function> dispatches the - highest priority event source that has a pending event. On - success, <function>sd_event_dispatch()</function> returns either - zero, which indicates that no further event sources may be - dispatched and exiting of the event loop was requested via - <citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>; - or a positive non-zero value, which means that an event source was - dispatched and the loop returned to its initial state, and the - caller should initiate the next event loop iteration by invoking - <function>sd_event_prepare()</function> again.</para> - - <para>In case <function>sd_event_prepare()</function> returned - zero, <function>sd_event_wait()</function> should be called to - wait for further events or a timeout. If any events are ready to - be processed, it returns a positive, non-zero value, and the - events should be dispatched with - <function>sd_event_dispatch()</function>. Otherwise, the event - loop returned to its initial state and the next event loop - iteration should be initiated by invoking - <function>sd_event_prepare()</function> again.</para> - - <para><function>sd_event_get_state()</function> may be used to - determine the state the event loop is currently in. It returns one - of the states described below.</para> - - <para><function>sd_event_get_iteration()</function> may be used to determine the current iteration of the event - loop. It returns an unsigned 64bit integer containing a counter that increases monotonically with each iteration of - the event loop, starting with 0. The counter is increased at the time of the - <function>sd_event_prepare()</function> invocation.</para> - - <para>All five functions take, as the first argument, the event loop object <parameter>event</parameter> that has - been created with <function>sd_event_new()</function>. The timeout for <function>sd_event_wait()</function> is - specified in <parameter>usec</parameter> in microseconds. <constant>(uint64_t) -1</constant> may be used to - specify an infinite timeout.</para> -</refsect1> - - <refsect1> - <title>State Machine</title> - - <para>The event loop knows the following states, that may be - queried with <function>sd_event_get_state()</function>.</para> - - <variablelist> - <varlistentry> - <term><constant>SD_EVENT_INITIAL</constant></term> - - <listitem><para>The initial state the event loop is in, - before each event loop iteration. Use - <function>sd_event_prepare()</function> to transition the - event loop into the <constant>SD_EVENT_ARMED</constant> or - <constant>SD_EVENT_PENDING</constant> states.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>SD_EVENT_PREPARING</constant></term> - - <listitem><para>An event source is currently being prepared, - i.e. the preparation handler is currently being executed, as - set with - <citerefentry><refentrytitle>sd_event_set_prepare</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This - state is only seen in the event source preparation handler - that is invoked from the - <function>sd_event_prepare()</function> call and is - immediately followed by <constant>SD_EVENT_ARMED</constant> or - <constant>SD_EVENT_PENDING</constant>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>SD_EVENT_ARMED</constant></term> - - <listitem><para><function>sd_event_prepare()</function> has - been called and no event sources were ready to be - dispatched. Use <function>sd_event_wait()</function> to wait - for new events, and transition into - <constant>SD_EVENT_PENDING</constant> or back into - <constant>SD_EVENT_INITIAL</constant>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>SD_EVENT_PENDING</constant></term> - - <listitem><para><function>sd_event_prepare()</function> or - <function>sd_event_wait()</function> have been called and - there were event sources with events pending. Use - <function>sd_event_dispatch()</function> to dispatch the - highest priority event source and transition back to - <constant>SD_EVENT_INITIAL</constant>, or - <constant>SD_EVENT_FINISHED</constant>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>SD_EVENT_RUNNING</constant></term> - - <listitem><para>A regular event source is currently being - dispatched. This state is only seen in the event source - handler that is invoked from the - <function>sd_event_dispatch()</function> call, and is - immediately followed by <constant>SD_EVENT_INITIAL</constant> - or <constant>SD_EVENT_FINISHED</constant> as soon the event - source handler returns. Note that during dispatching of exit - event sources the <constant>SD_EVENT_EXITING</constant> state - is seen instead.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>SD_EVENT_EXITING</constant></term> - - <listitem><para>Similar to - <constant>SD_EVENT_RUNNING</constant> but is the state in - effect while dispatching exit event sources. It is followed by - <constant>SD_EVENT_INITIAL</constant> or - <constant>SD_EVENT_FINISHED</constant> as soon as the event - handler returns.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>SD_EVENT_FINISHED</constant></term> - - <listitem><para>The event loop has exited. All exit event - sources have run. If the event loop is in this state it serves - no purpose anymore, and should be freed.</para></listitem> - </varlistentry> - - </variablelist> - - <para>A simplified flow chart of the states and the calls to - transition between them is shown below. Note that - <constant>SD_EVENT_PREPARING</constant>, - <constant>SD_EVENT_RUNNING</constant> and - <constant>SD_EVENT_EXITING</constant> are not shown here.</para> - - <programlisting> - INITIAL -<---<---<---<---<---<---<---<---<---<---<---<---\ - | | - | ^ - | | - v ret == 0 | - sd_event_prepare() >--->--->--->--->- ARMED | - | | ^ - | ret > 0 | | - | | | - v v ret == 0 | - PENDING <---<---<---<---<---< sd_event_wait() >--->--->--+ - | ret > 0 ^ - | | - | | - v | - sd_event_dispatch() >--->--->--->--->--->--->--->--->--->--->/ - | ret > 0 - | ret == 0 - | - v - FINISHED - </programlisting> - </refsect1> - - <refsect1> - <title>Return Value</title> - - <para>On success, these functions return 0 or a positive integer. - On failure, they return a negative errno-style error code. In case - of <function>sd_event_prepare()</function> and - <function>sd_event_wait()</function>, a positive, non-zero return - code indicates that events are ready to be processed and zero - indicates that no events are ready. In case of - <function>sd_event_dispatch()</function>, a positive, non-zero - return code indicates that the event loop returned to its initial - state and zero indicates the event loop has - exited. <function>sd_event_get_state()</function> returns a - positive or zero state on success.</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 <parameter>event</parameter> parameter is - invalid or <constant>NULL</constant>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>-EBUSY</constant></term> - - <listitem><para>The event loop object is not in the right - state.</para></listitem> - </varlistentry> - - <varlistentry> - <term><constant>-ESTALE</constant></term> - - <listitem><para>The event loop is already terminated.</para></listitem> - - </varlistentry> - - <varlistentry> - <term><constant>-ECHILD</constant></term> - - <listitem><para>The event loop has been created in a different process.</para></listitem> - - </varlistentry> - - </variablelist> - - <para>Other errors are possible, too.</para> - </refsect1> - - <xi:include href="libsystemd-pkgconfig.xml" /> - - <refsect1> - <title>See Also</title> - - <para> - <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_add_post</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_run</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_event_source_set_prepare</refentrytitle><manvolnum>3</manvolnum></citerefentry> - </para> - </refsect1> - -</refentry> |