systemd/man/sd_bus_unref.html
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<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</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="idm139798455485840"></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
object. This object is reference-counted, and will be destroyed
when all references are gone. Initially, the caller of this
function owns the sole reference.</p><p><code class="function">sd_bus_ref()</code> creates a new reference to
<em class="parameter"><code>bus</code></em>. This bus object will not be destroyed
until <code class="function">sd_bus_unref()</code> has been called as many
times plus once more. Once the reference count has dropped to
zero, <em class="parameter"><code>bus</code></em> cannot be used anymore, so
further calls to <code class="function">sd_bus_ref()</code> or
<code class="function">sd_bus_unref()</code> are illegal.</p><p><code class="function">sd_bus_unref()</code> destroys a reference to
<em class="parameter"><code>bus</code></em>.</p></div><div class="refsect1"><a name="idm139798455477696"></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
positive integer. On failure, it returns a negative errno-style
error code.</p><p><code class="function">sd_bus_ref</code> always returns the argument.
</p><p><code class="function">sd_bus_unref</code> always returns
<code class="constant">NULL</code>.</p></div><div class="refsect1"><a name="idm139798455473296"></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="constant">-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="idm139798459373072"></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
described here are available as a shared library, which can be
compiled and linked to with the
<code class="constant">libsystemd</code> <a href="http://linux.die.net/man/1/pkg-config"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
file.</p></div><div class="refsect1"><a name="idm139798459369648"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also"></a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
<a href="sd-bus.html"><span class="citerefentry"><span class="refentrytitle">sd-bus</span>(3)</span></a>,
<a href="sd_bus_open_user.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_open_user</span>(3)</span></a>,
<a href="sd_bus_open_system.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_open_system</span>(3)</span></a>,
<a href="sd_bus_default_user.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_default_user</span>(3)</span></a>,
<a href="sd_bus_default_system.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_default_system</span>(3)</span></a>
</p></div></div></body></html>