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systemd/man/sd_event_add_defer.xml

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man: drop mode line in file headers This is already included in .dir-locals, so we don't need it in the files themselves.
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<?xml version='1.0'?>
man: use same header for all files The "include" files had type "book" for some raeason. I don't think this is meaningful. Let's just use the same everywhere. $ perl -i -0pe 's^..DOCTYPE (book|refentry) PUBLIC "-//OASIS//DTD DocBook XML V4.[25]//EN"\s+"http^<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"\n "http^gms' man/*.xml
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
license: LGPL-2.1+ -> LGPL-2.1-or-later
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<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
man: document sd_event_add_{defer,post,exit}
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man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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<refentry id="sd_event_add_defer" xmlns:xi="http://www.w3.org/2001/XInclude">
man: document sd_event_add_{defer,post,exit}
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<refentryinfo>
<title>sd_event_add_defer</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_event_add_defer</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_event_add_defer</refname>
<refname>sd_event_add_post</refname>
<refname>sd_event_add_exit</refname>
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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<refname>sd_event_handler_t</refname>
man: document sd_event_add_{defer,post,exit}
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<refpurpose>Add static event sources to an event loop</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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<funcsynopsisinfo>#include &lt;systemd/sd-event.h&gt;</funcsynopsisinfo>
<funcsynopsisinfo><token>typedef</token> struct sd_event_source sd_event_source;</funcsynopsisinfo>
<funcprototype>
<funcdef>typedef int (*<function>sd_event_handler_t</function>)</funcdef>
<paramdef>sd_event_source *<parameter>s</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
</funcprototype>
man: document sd_event_add_{defer,post,exit}
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<funcprototype>
<funcdef>int <function>sd_event_add_defer</function></funcdef>
<paramdef>sd_event *<parameter>event</parameter></paramdef>
<paramdef>sd_event_source **<parameter>source</parameter></paramdef>
<paramdef>sd_event_handler_t <parameter>handler</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_event_add_post</function></funcdef>
<paramdef>sd_event *<parameter>event</parameter></paramdef>
<paramdef>sd_event_source **<parameter>source</parameter></paramdef>
<paramdef>sd_event_handler_t <parameter>handler</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_event_add_exit</function></funcdef>
<paramdef>sd_event *<parameter>event</parameter></paramdef>
<paramdef>sd_event_source **<parameter>source</parameter></paramdef>
<paramdef>sd_event_handler_t <parameter>handler</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
man: add better descriptions of what event handlers do The meaning of the return value, the default handlers, and loop exiting are now described.
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<para>These three functions add new static event sources to an event loop. The event loop object is
specified in the <parameter>event</parameter> parameter, the event source object is returned in the
<parameter>source</parameter> parameter. The event sources are enabled statically and will "fire" when
the event loop is run and the conditions described below are met.</para>
<para>The <parameter>handler</parameter> is a function to call or <constant>NULL</constant>. The handler
function will be passed the <parameter>userdata</parameter> pointer, which may be chosen freely by the
caller. The handler may return negative to signal an error (see below), other return values are
ignored. If <parameter>handler</parameter> is <constant>NULL</constant>, a default handler that calls
<citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry> will be
used.</para>
man: document sd_event_add_{defer,post,exit}
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<para><function>sd_event_add_defer()</function> adds a new event
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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source that will be dispatched instantly, before the event loop
goes to sleep again and waits for new events. By default, the
handler will be called once
(<constant>SD_EVENT_ONESHOT</constant>). Note that if the event
source is set to <constant>SD_EVENT_ON</constant> the event loop
man: fix typos
2015-12-27 01:25:49 +08:00
will never go to sleep again, but continuously call the handler,
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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possibly interleaved with other event sources.</para>
man: document sd_event_add_{defer,post,exit}
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man: sd_event_add_post - fix typo
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<para><function>sd_event_add_post()</function> adds a new event
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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source that is run before the event loop will sleep and wait
for new events, but only after at least one other non-post event
source was dispatched. By default, the source is enabled
permanently (<constant>SD_EVENT_ON</constant>). Note that this
event source type will still allow the event loop to go to sleep
again, even if set to <constant>SD_EVENT_ON</constant>, as long as
no other event source is ever triggered.</para>
man: document sd_event_add_{defer,post,exit}
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<para><function>sd_event_add_exit()</function> adds a new event
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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source that will be dispatched when the event loop is terminated
with <citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
man: document sd_event_add_{defer,post,exit}
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<para>The
<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
function may be used to enable the event source permanently
(<constant>SD_EVENT_ON</constant>) or to make it fire just once
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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(<constant>SD_EVENT_ONESHOT</constant>).</para>
man: add better descriptions of what event handlers do The meaning of the return value, the default handlers, and loop exiting are now described.
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<para>If the handler function returns a negative error code, it will either be disabled after the
invocation, even if the <constant>SD_EVENT_ON</constant> mode was requested before, or it will cause the
loop to terminate, see
<citerefentry><refentrytitle>sd_event_source_set_exit_on_failure</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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<para>To destroy an event source object use
<citerefentry><refentrytitle>sd_event_source_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
but note that the event source is only removed from the event loop
when all references to the event source are dropped. To make sure
an event source does not fire anymore, even when there's still a
reference to it kept, consider setting the event source to
<constant>SD_EVENT_OFF</constant> with
<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
sd-event: support callback=NULL in IO/child/inotify/defer event sources, too Also, document this functionality more prominently, including with a reference from sd_event_exit(). This is mostly to make things complete, as previously we supported NULL callbacks only in _add_time() and _add_signal(). However, I think this makes snese for IO event sources too (think: when some fd such as a pipe end sees SIGHUP or so, exit), as well as defer or post event sources (i.e. exit once we got nothing else to do). This also adds support for inotify event sources, simply to complete things (I can't see the immediate use, but maybe someone else comes up with it). The only event source type that doesn't allow callback=NULL now are exit callbacks, but for them they make little sense, as the event loop is exiting then anyway.
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<para>If the second parameter of these functions is passed as <constant>NULL</constant> no reference to
the event source object is returned. In this case the event source is considered "floating", and will be
destroyed implicitly when the event loop itself is destroyed.</para>
<para>If the <parameter>handler</parameter> parameter to <function>sd_event_add_defer()</function> or
<function>sd_event_add_post()</function> is <constant>NULL</constant>, and the event source fires, this
will be considered a request to exit the event loop. In this case, the <parameter>userdata</parameter>
parameter, cast to an integer, is passed as the exit code parameter to
<citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Similar
functionality is not available for <function>sd_event_add_exit()</function>, as these types of event
sources are only dispatched when exiting anyway.</para>
man: document sd_event_add_{defer,post,exit}
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</refsect1>
<refsect1>
<title>Return Value</title>
treewide: fix typos (#4802)
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<para>On success, these functions return 0 or a positive
man: document sd_event_add_{defer,post,exit}
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integer. On failure, they return a negative errno-style error
code.</para>
man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<refsect2>
<title>Errors</title>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<para>Returned errors may indicate the following problems:</para>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<variablelist>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<listitem><para>Not enough memory to allocate an object.</para></listitem>
</varlistentry>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<varlistentry>
<term><constant>-EINVAL</constant></term>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<listitem><para>An invalid argument has been passed.</para></listitem>
</varlistentry>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<varlistentry>
<term><constant>-ESTALE</constant></term>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<listitem><para>The event loop is already terminated.</para></listitem>
</varlistentry>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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<varlistentry>
<term><constant>-ECHILD</constant></term>
man: document sd_event_add_{defer,post,exit}
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sd-event: store and compare per-module static origin id sd-event objects use hashmaps, which use module-global state, so it is not safe to pass a sd-event object created by a module instance to another module instance (e.g.: when two libraries static linking sd-event are pulled in a single process). Initialize a random per-module origin id and store it in the object, and compare it when entering a public API, and error out if they don't match, together with the PID.
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<listitem><para>The event loop has been created in a different process, library or module instance.</para></listitem>
man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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</varlistentry>
man: document sd_event_add_{defer,post,exit}
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man: make separate "Errors" sections subsection of "Return value" Logically, this is better, because we're describing a subset of possible return values. Visually this also looks quite good because groff renders refsect2 much less prominently. Also rewrap things, add <constant> in various places, fix some typos.
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</variablelist>
</refsect2>
man: document sd_event_add_{defer,post,exit}
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</refsect1>
man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today.
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<xi:include href="libsystemd-pkgconfig.xml" />
man: document sd_event_add_{defer,post,exit}
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man: add version information for functions
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<refsect1>
<title>History</title>
man: condense version information for functions Use a more compact form like 'a, b, and c were added in version x'
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<para><function>sd_event_add_defer()</function>,
<function>sd_event_add_post()</function>,
<function>sd_event_add_exit()</function>, and
<function>sd_event_handler_t()</function> were added in version 217.</para>
man: add version information for functions
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</refsect1>
man: document sd_event_add_{defer,post,exit}
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<refsect1>
<title>See Also</title>
man: use <simplelist> for 'See also' sections This is just a slight markup improvement; there should be no difference in rendering.
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<para><simplelist type="inline">
<member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_now</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_source_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_source_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
</simplelist></para>
man: document sd_event_add_{defer,post,exit}
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</refsect1>
</refentry>
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