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diff --git a/man/sd_bus_message_read_basic.xml b/man/sd_bus_message_read_basic.xml new file mode 100644 index 0000000..774d3fc --- /dev/null +++ b/man/sd_bus_message_read_basic.xml @@ -0,0 +1,235 @@ +<?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_message_read_basic"> + + <refentryinfo> + <title>sd_bus_message_read_basic</title> + <productname>systemd</productname> + </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 <systemd/sd-bus.h></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 <constant>NULL</constant>, 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. See the table below for a complete list of allowed + types. + </para> + + <table id='format-specifiers'> + <title>Item type specifiers</title> + + <tgroup cols='4'> + <colspec colname='specifier' /> + <colspec colname='constant' /> + <colspec colname='description' /> + <colspec colname='ctype' /> + <thead> + <row> + <entry>Specifier</entry> + <entry>Constant</entry> + <entry>Description</entry> + <entry>Expected C Type</entry> + </row> + </thead> + <tbody> + <row> + <entry><literal>y</literal></entry> + <entry><constant>SD_BUS_TYPE_BYTE</constant></entry> + <entry>unsigned integer</entry> + <entry>uint8_t *</entry> + </row> + + <row> + <entry><literal>b</literal></entry> + <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry> + <entry>boolean</entry> + <entry>int *</entry> + </row> + + <row> + <entry><literal>n</literal></entry> + <entry><constant>SD_BUS_TYPE_INT16</constant></entry> + <entry>signed integer</entry> + <entry>int16_t *</entry> + </row> + + <row> + <entry><literal>q</literal></entry> + <entry><constant>SD_BUS_TYPE_UINT16</constant></entry> + <entry>unsigned integer</entry> + <entry>uint16_t *</entry> + </row> + + <row> + <entry><literal>i</literal></entry> + <entry><constant>SD_BUS_TYPE_INT32</constant></entry> + <entry>signed integer</entry> + <entry>int32_t *</entry> + </row> + + <row> + <entry><literal>u</literal></entry> + <entry><constant>SD_BUS_TYPE_UINT32</constant></entry> + <entry>unsigned integer</entry> + <entry>uint32_t *</entry> + </row> + + <row> + <entry><literal>x</literal></entry> + <entry><constant>SD_BUS_TYPE_INT64</constant></entry> + <entry>signed integer</entry> + <entry>int64_t *</entry> + </row> + + <row> + <entry><literal>t</literal></entry> + <entry><constant>SD_BUS_TYPE_UINT64</constant></entry> + <entry>unsigned integer</entry> + <entry>uint64_t *</entry> + </row> + + <row> + <entry><literal>d</literal></entry> + <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry> + <entry>floating-point</entry> + <entry>double *</entry> + </row> + + <row> + <entry><literal>s</literal></entry> + <entry><constant>SD_BUS_TYPE_STRING</constant></entry> + <entry>Unicode string</entry> + <entry>const char **</entry> + </row> + + <row> + <entry><literal>o</literal></entry> + <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry> + <entry>object path</entry> + <entry>const char **</entry> + </row> + + <row> + <entry><literal>g</literal></entry> + <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry> + <entry>signature</entry> + <entry>const char **</entry> + </row> + + <row> + <entry><literal>h</literal></entry> + <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry> + <entry>UNIX file descriptor</entry> + <entry>int *</entry> + </row> + </tbody> + </tgroup> + </table> + + <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 id='errors'> + <title>Errors</title> + + <para>Returned errors may indicate the following problems:</para> + + <variablelist> + <varlistentry> + <term><constant>-EINVAL</constant></term> + + <listitem><para>Specified type string is invalid or the message parameter is + <constant>NULL</constant>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ENXIO</constant></term> + + <listitem><para>The message does not contain the specified type at current + position.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-EBADMSG</constant></term> + + <listitem><para>The message cannot be parsed.</para></listitem> + </varlistentry> + </variablelist> + </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_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_message_skip</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |