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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
commit | 19f4f86bfed21c5326ed2acebe1163f3a83e832b (patch) | |
tree | d59b9989ce55ed23693e80974d94c856f1c2c8b1 /man/sd_bus_slot_set_userdata.xml | |
parent | Initial commit. (diff) | |
download | systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.tar.xz systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.zip |
Adding upstream version 241.upstream/241upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man/sd_bus_slot_set_userdata.xml')
-rw-r--r-- | man/sd_bus_slot_set_userdata.xml | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/man/sd_bus_slot_set_userdata.xml b/man/sd_bus_slot_set_userdata.xml new file mode 100644 index 0000000..dad708b --- /dev/null +++ b/man/sd_bus_slot_set_userdata.xml @@ -0,0 +1,88 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1+ --> + +<refentry id="sd_bus_slot_set_userdata" xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>sd_bus_slot_set_userdata</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_bus_slot_set_userdata</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_bus_slot_set_userdata</refname> + <refname>sd_bus_slot_get_userdata</refname> + + <refpurpose>Set and query the value in the "userdata" field</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>void* <function>sd_bus_slot_set_userdata</function></funcdef> + <paramdef>sd_bus_slot* <parameter>slot</parameter></paramdef> + <paramdef>void* <parameter>userdata</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>void* <function>sd_bus_slot_get_userdata</function></funcdef> + <paramdef>sd_bus_slot* <parameter>slot</parameter></paramdef> + </funcprototype> + + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>The userdata pointer allows data to be passed between the point where a callback is + registered, for example when a filter is added using + <citerefentry><refentrytitle>sd_bus_add_filter</refentrytitle><manvolnum>3</manvolnum></citerefentry> + or an asynchronous function call is made using + <citerefentry><refentrytitle>sd_bus_call_async</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + and the point where the callback is called, without having any global state. The pointer has + type <type>void*</type> and is not used by the sd-bus functions in any way, except to pass to + the callback function.</para> + + <para>Usually, the userdata field is set when the slot object is initially + registered. <function>sd_bus_slot_set_userdata()</function> may be used to change it later for + the bus slot object <parameter>slot</parameter>. Previous value of the field is returned. The + argument and returned value may be <constant>NULL</constant>. It will be passed as the + <parameter>userdata</parameter> argument to the callback function attached to the slot.</para> + + <para><function>sd_bus_slot_set_userdata()</function> gets the value of the userdata field in + the bus slot object <parameter>slot</parameter>.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, these functions return the value of the userdata field before the function + call. If the <parameter>slot</parameter> object is <constant>NULL</constant>, + <constant>NULL</constant> will be returned to signify an error, but this is not distinguishable + from the userdata field value being <constant>NULL</constant>.</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-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_slot_set_destroy_callback</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_slot_get_current_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |