man/sd_bus_ref.html

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  22   <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 214</span><hr><div class="refentry"><a name="sd_bus_new"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_bus_new, sd_bus_ref, sd_bus_unref — Create a new bus object and create or destroy references to it</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;systemd/sd-bus.h&gt;</pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_bus_new</b>(</code></td><td>sd_bus **<var class="pdparam">bus</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">sd_bus *<b class="fsfunc">sd_bus_ref</b>(</code></td><td>sd_bus *<var class="pdparam">bus</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">sd_bus *<b class="fsfunc">sd_bus_unref</b>(</code></td><td>sd_bus *<var class="pdparam">bus</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm214190756512"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_bus_new()</code> creates a new bus
  23     object. This object is reference-counted, and will be destroyed
  24     when all references are gone. Initially, the caller of this
  25     function owns the sole reference.</p><p><code class="function">sd_bus_ref()</code> creates a new reference to
  26     <em class="parameter"><code>bus</code></em>. This bus object will not be destroyed
  27     until <code class="function">sd_bus_unref()</code> has been called as many
  28     times plus once more. Once the reference count has dropped to
  29     zero, <em class="parameter"><code>bus</code></em> cannot be used anymore, so
  30     further calls to <code class="function">sd_bus_ref()</code> or
  31     <code class="function">sd_bus_unref()</code> are illegal.</p><p><code class="function">sd_bus_unref()</code> destroys a reference to
  32     <em class="parameter"><code>bus</code></em>.</p></div><div class="refsect1"><a name="idm214190317120"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p>On success, <code class="function">sd_bus_new()</code> returns 0 or a
  33     positive integer. On failure, it returns a negative errno-style
  34     error code.</p><p><code class="function">sd_bus_ref</code> always returns the argument.
  35     </p><p><code class="function">sd_bus_unref</code> always returns
  36     <code class="constant">NULL</code>.</p></div><div class="refsect1"><a name="idm214191774096"></a><h2 id="Errors">Errors<a class="headerlink" title="Permalink to this headline" href="#Errors">¶</a></h2><p>Returned errors may indicate the following problems:</p><div class="variablelist"><dl class="variablelist"><dt id="-ENOMEM"><span class="term"><code class="varname">-ENOMEM</code></span><a class="headerlink" title="Permalink to this term" href="#-ENOMEM">¶</a></dt><dd><p>Memory allocation failed.</p></dd></dl></div></div><div class="refsect1"><a name="idm214192238784"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p><code class="function">sd_bus_new()</code> and other functions
  37     described here are available as a shared library, which can be
  38     compiled and linked to with the
  39     <code class="constant">libsystemd</code> <a href="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
  40     file.</p></div><div class="refsect1"><a name="idm214192650416"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
  41       <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
  42       <a href="sd-bus.html"><span class="citerefentry"><span class="refentrytitle">sd-bus</span>(3)</span></a>,
  43       <a href="sd_bus_open_user.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_open_user</span>(3)</span></a>,
  44       <a href="sd_bus_open_system.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_open_system</span>(3)</span></a>,
  45       <a href="sd_bus_default_user.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_default_user</span>(3)</span></a>,
  46       <a href="sd_bus_default_system.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_default_system</span>(3)</span></a>
  47     </p></div></div></body></html>