man/sd_bus_can_send.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="sd_bus_can_send"
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>sd_bus_can_send</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>sd_bus_can_send</refentrytitle>
  16     <manvolnum>3</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>sd_bus_can_send</refname>
  21
  22     <refpurpose>Check which types can be sent over a bus object</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <funcsynopsis>
  27       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  28
  29       <funcprototype>
  30         <funcdef>void <function>sd_bus_can_send</function></funcdef>
  31         <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
  32         <paramdef>char <parameter>type</parameter></paramdef>
  33       </funcprototype>
  34     </funcsynopsis>
  35   </refsynopsisdiv>
  36
  37   <refsect1>
  38     <title>Description</title>
  39
  40     <para><function>sd_bus_can_send()</function> is mostly used for checking if file descriptor
  41     passing is available on the given bus. <parameter>type</parameter> can be any of the
  42     <constant>SD_BUS_TYPE</constant> constants.</para>
  43   </refsect1>
  44
  45   <refsect1>
  46     <title>Return Value</title>
  47
  48     <para>On failure, <function>sd_bus_can_send()</function> returns a negative errno-style error
  49     code. If values of the given type can be sent over the given bus, it returns a positive integer.
  50     Otherwise, it returns zero.</para>
  51
  52     <refsect2>
  53       <title>Errors</title>
  54
  55       <para>Returned errors may indicate the following problems:</para>
  56
  57       <variablelist>
  58         <varlistentry>
  59           <term><constant>-ENOPKG</constant></term>
  60
  61           <listitem><para>The bus object <parameter>bus</parameter> could not be resolved.</para>
  62
  63           <xi:include href="version-info.xml" xpointer="v246"/>
  64           </listitem>
  65         </varlistentry>
  66
  67         <varlistentry>
  68           <term><constant>-ENOTCONN</constant></term>
  69
  70           <listitem><para>The input parameter <parameter>bus</parameter> is
  71           <constant>NULL</constant> or the bus is not connected.</para>
  72
  73           <xi:include href="version-info.xml" xpointer="v246"/></listitem>
  74         </varlistentry>
  75
  76         <varlistentry>
  77           <term><constant>-ECHILD</constant></term>
  78
  79           <listitem><para>The bus object <parameter>bus</parameter> was created in a different
  80           process.</para>
  81
  82           <xi:include href="version-info.xml" xpointer="v246"/></listitem>
  83         </varlistentry>
  84       </variablelist>
  85     </refsect2>
  86   </refsect1>
  87
  88   <xi:include href="libsystemd-pkgconfig.xml" />
  89
  90   <refsect1>
  91     <title>History</title>
  92     <para><function>sd_bus_can_send()</function> was added in version 246.</para>
  93   </refsect1>
  94
  95   <refsect1>
  96     <title>See Also</title>
  97
  98     <para>
  99       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 100       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 101     </para>
 102   </refsect1>
 103
 104 </refentry>