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man: document some sd-bus functions (#3567)

* sd_bus_add_match
* sd_bus_get_fd
* sd_bus_message_read_basic
* sd_bus_process
This commit is contained in:
mahkoh 2016-06-21 17:52:32 +02:00 committed by Lennart Poettering
parent 7351ded5b9
commit e382c49f1d
5 changed files with 452 additions and 0 deletions

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@ -31,11 +31,13 @@ MANPAGES += \
man/sd-id128.3 \
man/sd-journal.3 \
man/sd_booted.3 \
man/sd_bus_add_match.3 \
man/sd_bus_creds_get_pid.3 \
man/sd_bus_creds_new_from_pid.3 \
man/sd_bus_default.3 \
man/sd_bus_error.3 \
man/sd_bus_error_add_map.3 \
man/sd_bus_get_fd.3 \
man/sd_bus_message_append.3 \
man/sd_bus_message_append_array.3 \
man/sd_bus_message_append_basic.3 \
@ -43,9 +45,11 @@ MANPAGES += \
man/sd_bus_message_append_strv.3 \
man/sd_bus_message_get_cookie.3 \
man/sd_bus_message_get_monotonic_usec.3 \
man/sd_bus_message_read_basic.3 \
man/sd_bus_negotiate_fds.3 \
man/sd_bus_new.3 \
man/sd_bus_path_encode.3 \
man/sd_bus_process.3 \
man/sd_bus_request_name.3 \
man/sd_event_add_child.3 \
man/sd_event_add_defer.3 \
@ -2522,11 +2526,13 @@ EXTRA_DIST += \
man/sd-journal.xml \
man/sd-login.xml \
man/sd_booted.xml \
man/sd_bus_add_match.xml \
man/sd_bus_creds_get_pid.xml \
man/sd_bus_creds_new_from_pid.xml \
man/sd_bus_default.xml \
man/sd_bus_error.xml \
man/sd_bus_error_add_map.xml \
man/sd_bus_get_fd.xml \
man/sd_bus_message_append.xml \
man/sd_bus_message_append_array.xml \
man/sd_bus_message_append_basic.xml \
@ -2534,9 +2540,11 @@ EXTRA_DIST += \
man/sd_bus_message_append_strv.xml \
man/sd_bus_message_get_cookie.xml \
man/sd_bus_message_get_monotonic_usec.xml \
man/sd_bus_message_read_basic.xml \
man/sd_bus_negotiate_fds.xml \
man/sd_bus_new.xml \
man/sd_bus_path_encode.xml \
man/sd_bus_process.xml \
man/sd_bus_request_name.xml \
man/sd_event_add_child.xml \
man/sd_event_add_defer.xml \

119
man/sd_bus_add_match.xml Normal file
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@ -0,0 +1,119 @@
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2016 Julian Orth
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="sd_bus_add_match">
<refentryinfo>
<title>sd_bus_add_match</title>
<productname>systemd</productname>
<authorgroup>
<author>
<firstname>Julian</firstname>
<surname>Orth</surname>
<email>ju.orth@gmail.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_add_match</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_add_match</refname>
<refpurpose>Add a match rule for message dispatching</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_add_match</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>sd_bus_slot **<parameter>slot</parameter></paramdef>
<paramdef>const char *<parameter>match</parameter></paramdef>
<paramdef>sd_bus_message_handler_t <parameter>callback</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>typedef int (*<function>sd_bus_message_handler_t</function>)</funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
<paramdef>sd_bus_error *<parameter>ret_error</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<function>sd_bus_add_match()</function> adds a match rule used to dispatch
incoming messages. The syntax of the rule passed in
<parameter>match</parameter> is described in the
<ulink url="https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus Specification</ulink>.
</para>
<para>
The message <parameter>m</parameter> passed to the callback is only
borrowed, that is, the callback should not call
<citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
on it. If the callback wants to hold on to the message beyond the lifetime
of the callback, it needs to call
<citerefentry><refentrytitle>sd_bus_message_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
to create a new reference.
</para>
<para>
If an error occurs during the callback invocation, the callback should
return a negative error number. If it wants other callbacks that match the
same rule to be called, it should return 0. Otherwise it should return a
positive integer.
</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>
On success, <function>sd_bus_add_match()</function> returns 0 or a
positive integer. On failure, it returns a negative errno-style error
code.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
</para>
</refsect1>
</refentry>

101
man/sd_bus_get_fd.xml Normal file
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@ -0,0 +1,101 @@
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2016 Julian Orth
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="sd_bus_get_fd">
<refentryinfo>
<title>sd_bus_get_fd</title>
<productname>systemd</productname>
<authorgroup>
<author>
<firstname>Julian</firstname>
<surname>Orth</surname>
<email>ju.orth@gmail.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_get_fd</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_get_fd</refname>
<refpurpose>Get the file descriptor connected to the message bus</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_get_fd</function></funcdef>
<paramdef>sd_bus *<parameter>bus</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 incmming messages.
</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>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>
Returns the file descriptor used for incoming messages from the message
bus.
</para>
</refsect1>
<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_set_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
</para>
</refsect1>
</refentry>

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@ -0,0 +1,113 @@
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2016 Julian Orth
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="sd_bus_message_read_basic">
<refentryinfo>
<title>sd_bus_message_read_basic</title>
<productname>systemd</productname>
<authorgroup>
<author>
<firstname>Julian</firstname>
<surname>Orth</surname>
<email>ju.orth@gmail.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_message_read_basic</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_message_read_basic</refname>
<refpurpose>Read a basic type from a message</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_message_read_basic</function></funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>char <parameter>type</parameter></paramdef>
<paramdef>void *<parameter>p</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<function>sd_bus_message_read_basic()</function> reads a basic type from a
message and advances the read position in the message. The set of basic
types and their ascii codes passed in <parameter>type</parameter> are
described in the <ulink
url="https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus
Specification</ulink>.
</para>
<para>
If <parameter>p</parameter> is not NULL, it should contain a pointer to an
appropriate object. For example, if <parameter>type</parameter> is
<constant>'y'</constant>, the object passed in <parameter>p</parameter>
should have type <code>uint8_t *</code>. If <parameter>type</parameter>
is <constant>'s'</constant>, the object passed in <parameter>p</parameter>
should have type <code>const char **</code>. Note that, if the basic type
is a pointer (e.g., <code>const char *</code> in the case of a string),
the pointer is only borrowed and the contents must be copied if they are
to be used after the end of the messages lifetime. Similarly, during the
lifetime of such a pointer, the message must not be modified.
</para>
<para>
If there is no object of the specified type at the current position in the
message, an error is returned.
</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>
On success, <function>sd_bus_message_read_basic()</function> returns 0 or
a positive integer. On failure, it returns a negative errno-style error
code.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
</para>
</refsect1>
</refentry>

111
man/sd_bus_process.xml Normal file
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@ -0,0 +1,111 @@
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2016 Julian Orth
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="sd_bus_process">
<refentryinfo>
<title>sd_bus_process</title>
<productname>systemd</productname>
<authorgroup>
<author>
<firstname>Julian</firstname>
<surname>Orth</surname>
<email>ju.orth@gmail.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_process</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_process</refname>
<refpurpose>Drive the connection</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_process</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>sd_bus_message **<parameter>r</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<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>
<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>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>
</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>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
</para>
</refsect1>
</refentry>