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Diffstat (limited to 'man/sd_bus_track_add_name.xml')
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diff --git a/man/sd_bus_track_add_name.xml b/man/sd_bus_track_add_name.xml new file mode 100644 index 0000000..ef304fc --- /dev/null +++ b/man/sd_bus_track_add_name.xml @@ -0,0 +1,231 @@ +<?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_track_add_name" xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>sd_bus_track_add_name</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_bus_track_add_name</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_bus_track_add_name</refname> + <refname>sd_bus_track_add_sender</refname> + <refname>sd_bus_track_remove_name</refname> + <refname>sd_bus_track_remove_sender</refname> + <refname>sd_bus_track_count</refname> + <refname>sd_bus_track_count_sender</refname> + <refname>sd_bus_track_count_name</refname> + <refname>sd_bus_track_contains</refname> + <refname>sd_bus_track_first</refname> + <refname>sd_bus_track_next</refname> + + <refpurpose>Add, remove and retrieve bus peers tracked in a bus peer tracking object</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_bus_track_add_name</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + <paramdef>const char* <parameter>name</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_track_add_sender</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + <paramdef>sd_bus_message* <parameter>message</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_track_remove_name</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + <paramdef>const char* <parameter>name</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_track_remove_sender</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + <paramdef>sd_bus_message* <parameter>message</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>unsigned <function>sd_bus_track_count</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_track_count_name</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + <paramdef>const char* <parameter>name</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_track_count_sender</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + <paramdef>sd_bus_message* <parameter>message</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_track_contains</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + <paramdef>const char* <parameter>name</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>const char* <function>sd_bus_track_first</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>const char* <function>sd_bus_track_next</function></funcdef> + <paramdef>sd_bus_track* <parameter>t</parameter></paramdef> + </funcprototype> + + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_bus_track_add_name()</function> adds a peer to track to a bus peer tracking object. The first + argument should refer to a bus peer tracking object created with + <citerefentry><refentrytitle>sd_bus_track_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, the second + name should refer to a D-Bus peer name to track, either in unique or well-known service format. If the name is not + tracked yet it will be added to the list of names to track. If it already is being tracked and non-recursive mode + is enabled, no operation is executed by this call. If recursive mode is enabled a per-name counter is increased by + one each time this call is invoked, and <function>sd_bus_track_remove_name()</function> has to be called as many + times as <function>sd_bus_track_add_name()</function> was invoked before in order to stop tracking of the name. Use + <citerefentry><refentrytitle>sd_bus_track_set_recursive</refentrytitle><manvolnum>3</manvolnum></citerefentry> to + switch from the default non-recursive mode to recursive mode, or back. Note that the specified name is tracked as + it is, well-known names are not resolved to unique names by this call. Note that multiple bus peer tracking objects + may track the same name.</para> + + <para><function>sd_bus_track_remove_name()</function> undoes the effect of + <function>sd_bus_track_add_name()</function> and removes a bus peer name from the list of peers to watch. Depending + on whether non-recursive or recursive mode is enabled for the bus peer tracking object this call will either remove + the name fully from the tracking object, or will simply decrement the per-name counter by one, removing the name + only when the counter reaches zero (see above). Note that a bus peer disconnecting from the bus will implicitly + remove its names fully from the bus peer tracking object, regardless of the current per-name counter.</para> + + <para><function>sd_bus_track_add_sender()</function> and <function>sd_bus_track_remove_sender()</function> are + similar to <function>sd_bus_track_add_name()</function> and <function>sd_bus_track_remove_name()</function> but + take a bus message as argument. The sender of this bus message is determined and added to/removed from the bus peer + tracking object. As messages always originate from unique names, and never from well-known names this means that + this call will effectively only add unique names to the bus peer tracking object.</para> + + <para><function>sd_bus_track_count()</function> returns the number of names currently being tracked by the + specified bus peer tracking object. Note that this function always returns the actual number of names tracked, and + hence if <function>sd_bus_track_add_name()</function> has been invoked multiple times for the same name it is only + counted as one, regardless if recursive mode is used or not.</para> + + <para><function>sd_bus_track_count_name()</function> returns the current per-name counter for the specified + name. If non-recursive mode is used this returns either 1 or 0, depending on whether the specified name has been + added to the tracking object before, or not. If recursive mode has been enabled, values larger than 1 may be + returned too, in case <function>sd_bus_track_add_name()</function> has been called multiple times for the same + name.</para> + + <para><function>sd_bus_track_count_sender()</function> is similar to + <function>sd_bus_track_count_name()</function>, but takes a bus message object and returns the per-name counter + matching the sender of the message.</para> + + <para><function>sd_bus_track_contains()</function> may be used to determine whether the specified name has been + added at least once to the specified bus peer tracking object.</para> + + <para><function>sd_bus_track_first()</function> and <function>sd_bus_track_next()</function> may be used to + enumerate all names currently being tracked by the passed bus peer tracking + object. <function>sd_bus_track_first()</function> returns the first entry in the object, and resets an internally + maintained read index. Each subsequent invocation of <function>sd_bus_track_next()</function> returns the next name + contained in the bus object. If the end is reached <constant>NULL</constant> is returned. If no names have been + added to the object yet <function>sd_bus_track_first()</function> will return <constant>NULL</constant> + immediately. The order in which names are returned is undefined; in particular which name is considered the first + returned is not defined. If recursive mode is enabled and the same name has been added multiple times to the bus + peer tracking object it is only returned once by this enumeration. If new names are added to or existing names + removed from the bus peer tracking object while it is being enumerated the enumeration ends on the next invocation + of <function>sd_bus_track_next()</function> as <constant>NULL</constant> is returned.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>sd_bus_track_add_name()</function> and <function>sd_bus_track_add_sender()</function> + return 0 if the specified name has already been added to the bus peer tracking object before and positive if it + hasn't. On failure, they return a negative errno-style error code.</para> + + <para><function>sd_bus_track_remove_name()</function> and <function>sd_bus_track_remove_sender()</function> return + positive if the specified name was previously tracked by the bus peer tracking object and has now been removed. In + non-recursive mode, 0 is returned if the specified name was not being tracked yet. In recursive mode + <constant>-EUNATCH</constant> is returned in this case. On failure, they return a negative errno-style error + code.</para> + + <para><function>sd_bus_track_count()</function> returns the number of names currently being tracked, or 0 on + failure.</para> + + <para><function>sd_bus_track_count_name()</function> and <function>sd_bus_track_count_sender()</function> return + the current per-name counter for the specified name or the sender of the specified message. Zero is returned for + names that are not being tracked yet, a positive value for names added at least once. Larger values than 1 are only + returned in recursive mode. On failure, a negative errno-style error code is returned.</para> + + <para><function>sd_bus_track_contains()</function> returns the passed name if it exists in the bus peer tracking + object. On failure, and if the name has not been added yet <constant>NULL</constant> is returned.</para> + + <para><function>sd_bus_track_first()</function> and <function>sd_bus_track_next()</function> return the first/next + name contained in the bus peer tracking object, and <constant>NULL</constant> if the end of the enumeration is + reached and on error.</para> + </refsect1> + + <refsect1> + <title>Errors</title> + + <para>Returned errors may indicate the following problems:</para> + + <variablelist> + + <varlistentry> + <term><constant>-EUNATCH</constant></term> + + <listitem><para><function>sd_bus_track_remove_name()</function> or + <function>sd_bus_track_remove_sender()</function> have been invoked for a name not previously added to the bus + peer object.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-EINVAL</constant></term> + + <listitem><para>Specified parameter is invalid.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ENOMEM</constant></term> + + <listitem><para>Memory allocation failed.</para></listitem> + </varlistentry> + + </variablelist> + </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_track_new</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |