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0c69794138
These lines are generally out-of-date, incomplete and unnecessary. With SPDX and git repository much more accurate and fine grained information about licensing and authorship is available, hence let's drop the per-file copyright notice. Of course, removing copyright lines of others is problematic, hence this commit only removes my own lines and leaves all others untouched. It might be nicer if sooner or later those could go away too, making git the only and accurate source of authorship information.
158 lines
6 KiB
XML
158 lines
6 KiB
XML
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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SPDX-License-Identifier: LGPL-2.1+
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-->
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<refentry id="sd_event_source_set_prepare" xmlns:xi="http://www.w3.org/2001/XInclude">
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<refentryinfo>
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<title>sd_event_source_set_prepare</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_event_source_set_prepare</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_event_source_set_prepare</refname>
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<refpurpose>Set a preparation callback for event sources</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_event_source_set_prepare</function></funcdef>
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<paramdef>sd_event_source *<parameter>source</parameter></paramdef>
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<paramdef>sd_event_handler_t <parameter>callback</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>typedef int (*<function>sd_event_handler_t</function>)</funcdef>
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<paramdef>sd_event_source *<parameter>s</parameter></paramdef>
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<paramdef>void *<parameter>userdata</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_event_source_set_prepare()</function> may be
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used to set a preparation callback for the event source object
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specified as <parameter>source</parameter>. The callback function
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specified as <parameter>callback</parameter> will be invoked
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immediately before the event loop goes to sleep to wait for
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incoming events. It is invoked with the user data pointer passed
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when the event source was created. The event source will be disabled
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if the callback function returns a negative error code. The callback
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function may be used to reconfigure the precise events to wait for.
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If the <parameter>callback</parameter> parameter is passed as NULL
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the callback function is reset. </para>
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<para>Event source objects have no preparation callback associated
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when they are first created with calls such as
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<citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Preparation
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callback functions are supported for all event source types with
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the exception of those created with
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<citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Preparation
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callback functions are dispatched in the order indicated by the
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event source's priority field, as set with
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<citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Preparation
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callbacks of disabled event sources (see
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<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>)
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are not invoked.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success,
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<function>sd_event_source_set_prepare()</function> returns a
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non-negative integer. On failure, it returns a negative
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errno-style error code.</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-EINVAL</constant></term>
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<listitem><para><parameter>source</parameter> is not a valid
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pointer to an <structname>sd_event_source</structname>
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object.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ESTALE</constant></term>
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<listitem><para>The event loop is already terminated.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENOMEM</constant></term>
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<listitem><para>Not enough memory.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ECHILD</constant></term>
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<listitem><para>The event loop has been created in a different process.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EDOM</constant></term>
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<listitem><para>The specified event source has been created
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with
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<citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<xi:include href="libsystemd-pkgconfig.xml" />
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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