systemd/man/sd_bus_message_append_array.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

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<refentry id="sd_bus_message_append_array" conditional="ENABLE_KDBUS"
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>sd_bus_message_append_array</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>A monkey with a typewriter</contrib>
        <firstname>Zbigniew</firstname>
        <surname>Jędrzejewski-Szmek</surname>
        <email>zbyszek@in.waw.pl</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>sd_bus_message_append_array</refentrytitle>
    <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>sd_bus_message_append_array</refname>
    <refname>sd_bus_message_append_array_memfd</refname>
    <refname>sd_bus_message_append_array_iovec</refname>
    <refname>sd_bus_message_append_array_space</refname>

    <refpurpose>Attach an array of items to a message</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <funcsynopsis>
      <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>

      <funcprototype>
        <funcdef>int sd_bus_message_append_array</funcdef>
        <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
        <paramdef>char <parameter>type</parameter></paramdef>
        <paramdef>char void *<parameter>ptr</parameter></paramdef>
        <paramdef>size_t <parameter>size</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int sd_bus_message_append_array_memfd</funcdef>
        <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
        <paramdef>char <parameter>type</parameter></paramdef>
        <paramdef>int <parameter>memfd</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int sd_bus_message_append_array_iovec</funcdef>
        <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
        <paramdef>char <parameter>type</parameter></paramdef>
        <paramdef>const struct iovec *<parameter>iov</parameter></paramdef>
        <paramdef>unsigned <parameter>n</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int sd_bus_message_append_array_space</funcdef>
        <paramdef>char <parameter>type</parameter></paramdef>
        <paramdef>size_t <parameter>size</parameter></paramdef>
        <paramdef>char void **<parameter>ptr</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>The <function>sd_bus_message_append_array</function> functionc
    appends items to message <parameter>m</parameter> as the single
    array. A container will be opened, items appended, and the
    container closed. Parameter <parameter>type</parameter> determines
    how pointer <parameter>p</parameter> is interpreted.
    <parameter>type</parameter> must be one of the "trivial" types
    <literal>y</literal>, <literal>n</literal>, <literal>q</literal>,
    <literal>i</literal>, <literal>u</literal>, <literal>x</literal>,
    <literal>t</literal>, <literal>d</literal> (but not
    <literal>b</literal>), as defined by the
    <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html#basic-types">Basic Types</ulink>
    section of the D-Bus specification, and listed in
    <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
    Pointer <parameter>p</parameter> must point to an array of size
    <parameter>size</parameter> bytes containing items of the
    respective type. Size <parameter>size</parameter> must be a
    multiple of the size of the type <parameter>type</parameter>. As a
    special case, <parameter>p</parameter> may be
    <constant>NULL</constant>, if <parameter>size</parameter> is 0.
    </para>

    <para>The memory pointed at by <parameter>p</parameter> is copied
    into the memory area containing the message and may be changed
    after this call.</para>

    <para>The
    <function>sd_bus_message_append_array_memfd</function> function appends
    items to message <parameter>m</parameter>, similarly to
    <function>sd_bus_message_append_array</function>. Contents of the
    memory file descriptor <parameter>memfd</parameter> are used as
    the contents of the array. Their size must be a multiple of the
    size of the type <parameter>type</parameter>.</para>

    <para>The descriptor specified with <parameter>memfd</parameter>
    will be sealed and cannot be modified after this call.</para>

    <para>The
    <function>sd_bus_message_append_array_iovec</function> function appends
    items to message <parameter>m</parameter>, similarly to
    <function>sd_bus_message_append_array</function>. Contents of the
    iovec <parameter>iov</parameter> are used as the contents of the
    array. The total size of <parameter>iov</parameter> payload (the
    sum of <structfield>iov_len</structfield> fields) must be a multiple
    of the size of the type <parameter>type</parameter>.</para>

    <para>The <parameter>iov</parameter> argument must point to
    <parameter>n</parameter> <structname>struct iovec</structname>
    structures. Each structure may have the
    <structname>iov_base</structname> field set, in which case the
    memory pointed to will be copied into the message, or unset, in
    which case a block of zeros of length
    <structname>iov_len</structname> bytes will be inserted. The
    memory pointed at by <parameter>iov</parameter> may be changed
    after this call.</para>

    <para>The
    <function>sd_bus_message_append_array_space</function> function appends
    space for an array of items to message <parameter>m</parameter>.
    It behaves the same as
    <function>sd_bus_message_append_array</function>, but instead
    of copying items to the message, it returns a pointer to the
    destination area to the caller in pointer <parameter>p</parameter>.
    </para>
  </refsect1>

  <refsect1>
    <title>Return Value</title>

    <para>On success, these calls return 0 or a positive integer. On
    failure, they returns a negative errno-style error code.</para>
  </refsect1>

  <xi:include href="sd_bus_message_append_basic.xml" xpointer="errors" />

  <refsect1>
    <title>Notes</title>

    <para><function>sd_bus_append_array()</function> and other
    functions described here are available as a shared library, which
    can be compiled and linked to with the
    <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    file.</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_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink>
    </para>
  </refsect1>

</refentry>