man: substantially update the docs regarding hooking sd-bus objects up with external event loops
Prompted by https://lists.freedesktop.org/archives/systemd-devel/2018-December/041817.html This also drops all references to select() from our manpages. It's 2018 after all, people should use poll(), or ppoll() or epoll().
This commit is contained in:
Lennart Poettering
parent
41fc3fab1c
commit
ffd1a3f688
|
|
@ -194,7 +194,7 @@ manpages = [
|
|||
'3',
|
||||
['SD_BUS_ERROR_END', 'SD_BUS_ERROR_MAP', 'sd_bus_error_map'],
|
||||
''],
|
||||
['sd_bus_get_fd', '3', [], ''],
|
||||
['sd_bus_get_fd', '3', ['sd_bus_get_events', 'sd_bus_get_timeout'], ''],
|
||||
['sd_bus_get_n_queued_read', '3', ['sd_bus_get_n_queued_write'], ''],
|
||||
['sd_bus_is_open', '3', ['sd_bus_is_ready'], ''],
|
||||
['sd_bus_message_append', '3', ['sd_bus_message_appendv'], ''],
|
||||
|
|
@ -347,6 +347,7 @@ manpages = [
|
|||
'sd_bus_track_unref',
|
||||
'sd_bus_track_unrefp'],
|
||||
''],
|
||||
['sd_bus_wait', '3', [], ''],
|
||||
['sd_event_add_child',
|
||||
'3',
|
||||
['sd_event_child_handler_t', 'sd_event_source_get_child_pid'],
|
||||
|
|
|
|||
|
|
@ -71,6 +71,13 @@
|
|||
|
||||
<para>The <function>sd_bus_get_event()</function> returns the event loop object the specified bus object is
|
||||
currently attached to, or <constant>NULL</constant> if it is currently not attached to any.</para>
|
||||
|
||||
<para>Note that <function>sd_bus_attach_event()</function> is only one of three supported ways to implement I/O
|
||||
event handling for bus connections. Alternatively use
|
||||
<citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry> for hooking up a
|
||||
bus connection object with external or manual event loops. Or use
|
||||
<citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry> as a simple
|
||||
synchronous, blocking I/O waiting call.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
|
|
@ -107,7 +114,8 @@
|
|||
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_set_close_on_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
<citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
|
|
|
|||
|
|
@ -8,7 +8,7 @@
|
|||
Copyright © 2016 Julian Orth
|
||||
-->
|
||||
|
||||
<refentry id="sd_bus_get_fd">
|
||||
<refentry id="sd_bus_get_fd" xmlns:xi="http://www.w3.org/2001/XInclude">
|
||||
|
||||
<refentryinfo>
|
||||
<title>sd_bus_get_fd</title>
|
||||
|
|
@ -22,8 +22,10 @@
|
|||
|
||||
<refnamediv>
|
||||
<refname>sd_bus_get_fd</refname>
|
||||
<refname>sd_bus_get_events</refname>
|
||||
<refname>sd_bus_get_timeout</refname>
|
||||
|
||||
<refpurpose>Get the file descriptor connected to the message bus</refpurpose>
|
||||
<refpurpose>Get the file descriptor, I/O events and time-out to wait for from a message bus object</refpurpose>
|
||||
</refnamediv>
|
||||
|
||||
<refsynopsisdiv>
|
||||
|
|
@ -34,39 +36,113 @@
|
|||
<funcdef>int <function>sd_bus_get_fd</function></funcdef>
|
||||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||||
</funcprototype>
|
||||
|
||||
<funcprototype>
|
||||
<funcdef>int <function>sd_bus_get_events</function></funcdef>
|
||||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||||
</funcprototype>
|
||||
|
||||
<funcprototype>
|
||||
<funcdef>int <function>sd_bus_get_timeout</function></funcdef>
|
||||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||||
<paramdef>uint64_t *<parameter>timeout_usec</parameter></paramdef>
|
||||
</funcprototype>
|
||||
</funcsynopsis>
|
||||
</refsynopsisdiv>
|
||||
|
||||
<refsect1>
|
||||
<title>Description</title>
|
||||
|
||||
<para>
|
||||
<function>sd_bus_get_fd()</function> returns the file descriptor used to
|
||||
communicate with the message bus. This descriptor can be used with
|
||||
<citerefentry
|
||||
project='die-net'><refentrytitle>select</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry
|
||||
project='die-net'><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
or similar functions to wait for incoming messages.
|
||||
</para>
|
||||
<para><function>sd_bus_get_fd()</function> returns the file descriptor used to communicate from a message bus
|
||||
object. This descriptor can be used with <citerefentry
|
||||
project='man-pages'><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry> or a similar
|
||||
function to wait for I/O events on the specified bus connection object. If the bus object was configured with the
|
||||
<citerefentry><refentrytitle>sd_bus_set_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry> function, then
|
||||
the <parameter>input_fd</parameter> file descriptor used in that call is returned.</para>
|
||||
|
||||
<para>
|
||||
If the bus was created with the
|
||||
<citerefentry><refentrytitle>sd_bus_set_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
function, then the <parameter>input_fd</parameter> used in that call is
|
||||
returned.
|
||||
</para>
|
||||
<para><function>sd_bus_get_events()</function> returns the I/O events to wait for, suitable for passing to
|
||||
<function>poll()</function> or a similar call. Returns a combination of <constant>POLLIN</constant>,
|
||||
<constant>POLLOUT</constant>, … events, or negative on error.</para>
|
||||
|
||||
<para><function>sd_bus_get_timeout()</function> returns the time-out in µs to pass to to
|
||||
<function>poll()</function> or a similar call when waiting for events on the specified bus connection. The returned
|
||||
time-out may be zero, in which case a subsequent I/O polling call should be invoked in non-blocking mode. The
|
||||
returned timeout may be <constant>UINT64_MAX</constant> in which case the I/O polling call may block indefinitely,
|
||||
without any applied time-out. Note that the returned time-out should be considered only a maximum sleeping time. It
|
||||
is permissible (and even expected) that shorter time-outs are used by the calling program, in case other event
|
||||
sources are polled in the same event loop. Note that the returned time-value is relative and specified in
|
||||
microseconds. When converting this value in order to pass it as third argument to <function>poll()</function>
|
||||
(which expects milliseconds), care should be taken to use a division that rounds up to ensure the I/O polling
|
||||
operation doesn't sleep for shorter than necessary, which might result in unintended busy looping (alternatively,
|
||||
use <citerefentry project='man-pages'><refentrytitle>ppoll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
instead of plain <function>poll()</function>, which understands time-outs with nano-second granularity).</para>
|
||||
|
||||
<para>These three functions are useful to hook up a bus connection object with an external or manual event loop
|
||||
involving <function>poll()</function> or a similar I/O polling call. Before each invocation of the I/O polling
|
||||
call, all three functions should be invoked: the file descriptor returned by <function>sd_bus_get_fd()</function>
|
||||
should be polled for the events indicated by <function>sd_bus_get_events()</function>, and the I/O call should
|
||||
block for that up to the time-out returned by <function>sd_bus_get_timeout()</function>. After each I/O polling
|
||||
call the bus connection needs to process incoming or outgoing data, by invoking
|
||||
<citerefentry><refentrytitle>sd_bus_process</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
|
||||
|
||||
<para>Note that these function are only one of three supported ways to implement I/O event handling for bus
|
||||
connections. Alternatively use
|
||||
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry> to attach a
|
||||
bus connection to an <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
event loop. Or use <citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
as a simple synchronous, blocking I/O waiting call.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Return Value</title>
|
||||
|
||||
<para>
|
||||
Returns the file descriptor used for incoming messages from the message
|
||||
bus.
|
||||
</para>
|
||||
<para><function>sd_bus_get_fd()</function> returns the file descriptor used for communication, or a negative
|
||||
<varname>errno</varname>-style error code on error.</para>
|
||||
|
||||
<para><function>sd_bus_get_events()</function> returns the I/O event mask to use for I/O event watching, or a
|
||||
negative <varname>errno</varname>-style error code on error.</para>
|
||||
|
||||
<para><function>sd_bus_get_timeout()</function> returns zero or positive on success, or a negative
|
||||
<varname>errno</varname>-style error code on error.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Errors</title>
|
||||
|
||||
<para>Returned errors may indicate the following problems:</para>
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><constant>-EINVAL</constant></term>
|
||||
|
||||
<listitem><para>An invalid bus object was passed.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ECHILD</constant></term>
|
||||
|
||||
<listitem><para>The bus connection was allocated in a parent process and is being reused in a child process
|
||||
after <function>fork()</function>.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ENOTCONN</constant></term>
|
||||
|
||||
<listitem><para>The bus connection has been terminated.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-EPERM</constant></term>
|
||||
|
||||
<listitem><para>Two distinct file descriptors were passed for input and output using
|
||||
<function>sd_bus_set_fd()</function>, which <function>sd_bus_get_fd()</function> cannot
|
||||
return.</para></listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</refsect1>
|
||||
|
||||
<xi:include href="libsystemd-pkgconfig.xml" />
|
||||
|
||||
<refsect1>
|
||||
<title>See Also</title>
|
||||
|
||||
|
|
@ -74,6 +150,10 @@
|
|||
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_set_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_process</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry project='man-pages'><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
|
|
|
|||
|
|
@ -8,7 +8,7 @@
|
|||
Copyright © 2016 Julian Orth
|
||||
-->
|
||||
|
||||
<refentry id="sd_bus_process">
|
||||
<refentry id="sd_bus_process" xmlns:xi="http://www.w3.org/2001/XInclude">
|
||||
|
||||
<refentryinfo>
|
||||
<title>sd_bus_process</title>
|
||||
|
|
@ -33,7 +33,7 @@
|
|||
<funcprototype>
|
||||
<funcdef>int <function>sd_bus_process</function></funcdef>
|
||||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||||
<paramdef>sd_bus_message **<parameter>r</parameter></paramdef>
|
||||
<paramdef>sd_bus_message **<parameter>ret</parameter></paramdef>
|
||||
</funcprototype>
|
||||
</funcsynopsis>
|
||||
</refsynopsisdiv>
|
||||
|
|
@ -41,49 +41,92 @@
|
|||
<refsect1>
|
||||
<title>Description</title>
|
||||
|
||||
<para>
|
||||
<function>sd_bus_process()</function> drives the connection between the
|
||||
message bus and the client. That is, it handles connecting,
|
||||
authentication, and message processing. It should be called in a loop
|
||||
until no further progress can be made or an error occurs.
|
||||
<para><function>sd_bus_process()</function> drives the connection between the client and the message bus. That is,
|
||||
it handles connecting, authentication, and message processing. When invoked pending I/O work is executed, and
|
||||
queued incoming messages are dispatched to registered callbacks. Each time it is invoked a single operation is
|
||||
executed. It returns zero when no operations were pending and positive if a message was processed. When zero is
|
||||
returned the caller should synchronously poll for I/O events before calling into
|
||||
<function>sd_bus_process()</function> again. For that either user the simple, synchronous
|
||||
<citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry> call, or hook up
|
||||
the bus connection object to an external or manual event loop using
|
||||
<citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Once no further progress can be made,
|
||||
<citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
should be called. Alternatively the user can wait for incoming data on
|
||||
the file descriptor returned by
|
||||
<citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
||||
</para>
|
||||
<para><function>sd_bus_process()</function> processes at most one incoming message per call. If the parameter
|
||||
<parameter>ret</parameter> is not <constant>NULL</constant> and the call processed a message,
|
||||
<parameter>*ret</parameter> is set to this message. The caller owns a reference to this message and should call
|
||||
<citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> when the
|
||||
message is no longer needed. If <parameter>ret</parameter> is not NULL, progress was made, but no message was
|
||||
processed, <parameter>*ret</parameter> is set to <constant>NULL</constant>.</para>
|
||||
|
||||
<para>
|
||||
<function>sd_bus_process</function> processes at most one incoming
|
||||
message per call. If the parameter <parameter>r</parameter> is not NULL
|
||||
and the call processed a message, <code>*r</code> is set to this message.
|
||||
The caller owns a reference to this message and should call
|
||||
<citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
when the message is no longer needed. If <parameter>r</parameter> is not
|
||||
NULL, progress was made, but no message was processed, <code>*r</code> is
|
||||
set to NULL.
|
||||
</para>
|
||||
<para>If a the bus object is connected to an
|
||||
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> event loop (with
|
||||
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>), it is not
|
||||
necessary to call <function>sd_bus_process()</function> directly as it is invoked automatically when
|
||||
necessary.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Return Value</title>
|
||||
|
||||
<para>
|
||||
If progress was made, a positive integer is returned. If no progress was
|
||||
made, 0 is returned. If an error occurs, a negative errno-style error code
|
||||
is returned.
|
||||
</para>
|
||||
<para>If progress was made, a positive integer is returned. If no progress was made, 0 is returned. If an error
|
||||
occurs, a negative <varname>errno</varname>-style error code is returned.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Errors</title>
|
||||
|
||||
<para>Returned errors may indicate the following problems:</para>
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><constant>-EINVAL</constant></term>
|
||||
|
||||
<listitem><para>An invalid bus object was passed.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ECHILD</constant></term>
|
||||
|
||||
<listitem><para>The bus connection was allocated in a parent process and is being reused in a child process
|
||||
after <function>fork()</function>.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ENOTCONN</constant></term>
|
||||
|
||||
<listitem><para>The bus connection has been terminated already.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ECONNRESET</constant></term>
|
||||
|
||||
<listitem><para>The bus connection has been terminated just now.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-EBUSY</constant></term>
|
||||
|
||||
<listitem><para>This function is already being called, i.e. <function>sd_bus_process()</function> has been
|
||||
called from a callback function that itself was called by
|
||||
<function>sd_bus_process()</function>.</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_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,113 @@
|
|||
<?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+
|
||||
|
||||
Copyright © 2016 Julian Orth
|
||||
-->
|
||||
|
||||
<refentry id="sd_bus_wait" xmlns:xi="http://www.w3.org/2001/XInclude">
|
||||
|
||||
<refentryinfo>
|
||||
<title>sd_bus_wait</title>
|
||||
<productname>systemd</productname>
|
||||
</refentryinfo>
|
||||
|
||||
<refmeta>
|
||||
<refentrytitle>sd_bus_wait</refentrytitle>
|
||||
<manvolnum>3</manvolnum>
|
||||
</refmeta>
|
||||
|
||||
<refnamediv>
|
||||
<refname>sd_bus_wait</refname>
|
||||
|
||||
<refpurpose>Wait for I/O on a bus connection</refpurpose>
|
||||
</refnamediv>
|
||||
|
||||
<refsynopsisdiv>
|
||||
<funcsynopsis>
|
||||
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
|
||||
|
||||
<funcprototype>
|
||||
<funcdef>int <function>sd_bus_wait</function></funcdef>
|
||||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||||
<paramdef>uint64_t <parameter>timeout_usec</parameter></paramdef>
|
||||
</funcprototype>
|
||||
</funcsynopsis>
|
||||
</refsynopsisdiv>
|
||||
|
||||
<refsect1>
|
||||
<title>Description</title>
|
||||
|
||||
<para><function>sd_bus_wait()</function> synchronously waits for I/O on the specified bus connection object. This
|
||||
function is supposed to be called whenever
|
||||
<citerefentry><refentrytitle>sd_bus_process</refentrytitle><manvolnum>3</manvolnum></citerefentry> returns zero,
|
||||
indicating that no work is pending on the connection. Internally, this call invokes <citerefentry
|
||||
project='man-pages'><refentrytitle>ppoll</refentrytitle><manvolnum>3</manvolnum></citerefentry>, to wait for I/O on
|
||||
the bus connection. If the <parameter>timeout_sec</parameter> parameter is specified, the call will block at most
|
||||
for the specified amount of time in µs. Pass <constant>UINT64_MAX</constant> to permit it to sleep
|
||||
indefinitely.</para>
|
||||
|
||||
<para>After each invocation of <function>sd_bus_wait()</function> the <function>sd_bus_process()</function> call
|
||||
should be invoked in order to process any now pending I/O work.</para>
|
||||
|
||||
<para>Note that <function>sd_bus_wait()</function> is suitable only for simple programs as it does not permit
|
||||
waiting for other I/O events. For more complex programs either connect the bus connection object to an external
|
||||
event loop using <citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
or to an <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> event loop
|
||||
using
|
||||
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Return Value</title>
|
||||
|
||||
<para>If any I/O was seen, a positive value is returned, zero otherwise. If an error occurs, a negative
|
||||
<varname>errno</varname>-style error code is returned.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Errors</title>
|
||||
|
||||
<para>Returned errors may indicate the following problems:</para>
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><constant>-EINVAL</constant></term>
|
||||
|
||||
<listitem><para>An invalid bus object was passed.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ECHILD</constant></term>
|
||||
|
||||
<listitem><para>The bus connection was allocated in a parent process and is being reused in a child process
|
||||
after <function>fork()</function>.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ENOTCONN</constant></term>
|
||||
|
||||
<listitem><para>The bus connection has been terminated already.</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_process</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
</refentry>
|
||||
Loading…
Reference in New Issue