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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>sd_bus_request_name</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
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<span style="float:right">systemd 221</span><hr><div class="refentry"><a name="sd_bus_request_name"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_bus_request_name, sd_bus_release_name — Request or release a well-known name on a bus</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include <systemd/sd-bus.h></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_request_name</b>(</code></td><td>sd_bus *<var class="pdparam">bus</var>, </td></tr><tr><td> </td><td>const char *<var class="pdparam">name</var>, </td></tr><tr><td> </td><td>uint64_t <var class="pdparam">flags</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">int <b class="fsfunc">sd_bus_release_name</b>(</code></td><td>sd_bus *<var class="pdparam">bus</var>, </td></tr><tr><td> </td><td>const char *<var class="pdparam">name</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm47944166763568"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_bus_request_name()</code> requests a
well-known name on a bus. It takes a bus connection, a valid bus
name and a flags parameter. The flags parameter is a combination
of the following flags:</p><div class="variablelist"><dl class="variablelist"><dt id="SD_BUS_NAME_ALLOW_REPLACEMENT"><span class="term"><code class="varname">SD_BUS_NAME_ALLOW_REPLACEMENT</code></span><a class="headerlink" title="Permalink to this term" href="#SD_BUS_NAME_ALLOW_REPLACEMENT">¶</a></dt><dd><p>After acquiring the name successfully, permit
other peers to take over the name when they try to acquire it
with the <code class="varname">SD_BUS_NAME_REPLACE_EXISTING</code> flag
set. If <code class="varname">SD_BUS_NAME_ALLOW_REPLACEMENT</code> is
not set on the original request, such a request by other peers
will be denied.</p></dd><dt id="SD_BUS_NAME_REPLACE_EXISTING"><span class="term"><code class="varname">SD_BUS_NAME_REPLACE_EXISTING</code></span><a class="headerlink" title="Permalink to this term" href="#SD_BUS_NAME_REPLACE_EXISTING">¶</a></dt><dd><p>Take over the name if it is already acquired
by another peer, and that other peer has permitted takeover by
setting <code class="varname">SD_BUS_NAME_ALLOW_REPLACEMENT</code> while
acquiring it.</p></dd><dt id="SD_BUS_NAME_QUEUE"><span class="term"><code class="varname">SD_BUS_NAME_QUEUE</code></span><a class="headerlink" title="Permalink to this term" href="#SD_BUS_NAME_QUEUE">¶</a></dt><dd><p>Queue the acquisition of the name when the
name is already taken.</p></dd></dl></div><p><code class="function">sd_bus_release_name()</code> releases an
acquired well-known name. It takes a bus connection and a valid
bus name as parameters.</p></div><div class="refsect1"><a name="idm47944167009184"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p>On success, these calls return 0 or a positive integer. On
failure, these calls return a negative errno-style error
code.</p><p>If <code class="varname">SD_BUS_NAME_QUEUE</code> is specified,
<code class="function">sd_bus_request_name()</code> will return 0 when the
name is already taken by another peer and the client has been
added to the queue for the name. In that case, the caller can
subscribe to "<code class="literal">NameOwnerChanged</code>" signals to be
notified when the name is successfully acquired.
<code class="function">sd_bus_request_name()</code> returns > 0 when the
name has immediately been acquired successfully.</p></div><div class="refsect1"><a name="idm47944167816352"></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="-EALREADY"><span class="term"><code class="constant">-EALREADY</code></span><a class="headerlink" title="Permalink to this term" href="#-EALREADY">¶</a></dt><dd><p>The caller already is the owner of the
specified name.</p></dd><dt id="-EEXIST"><span class="term"><code class="constant">-EEXIST</code></span><a class="headerlink" title="Permalink to this term" href="#-EEXIST">¶</a></dt><dd><p>The name has already been acquired by a
different peer, and SD_BUS_NAME_REPLACE_EXISTING was not
specified or the other peer did not specify
SD_BUS_NAME_ALLOW_REPLACEMENT while acquiring the
name.</p></dd><dt id="-ESRCH"><span class="term"><code class="constant">-ESRCH</code></span><a class="headerlink" title="Permalink to this term" href="#-ESRCH">¶</a></dt><dd><p>It was attempted to release a name that is
currently not registered on the bus.</p></dd><dt id="-EADDRINUSE"><span class="term"><code class="constant">-EADDRINUSE</code></span><a class="headerlink" title="Permalink to this term" href="#-EADDRINUSE">¶</a></dt><dd><p>It was attempted to release a name that is
owned by a different peer on the bus.</p></dd><dt id="-EINVAL"><span class="term"><code class="constant">-EINVAL</code></span><a class="headerlink" title="Permalink to this term" href="#-EINVAL">¶</a></dt><dd><p>A specified parameter is
invalid.</p></dd><dt id="-ENOTCONN"><span class="term"><code class="constant">-ENOTCONN</code></span><a class="headerlink" title="Permalink to this term" href="#-ENOTCONN">¶</a></dt><dd><p>The bus connection has been
disconnected.</p></dd><dt id="-ECHILD"><span class="term"><code class="constant">-ECHILD</code></span><a class="headerlink" title="Permalink to this term" href="#-ECHILD">¶</a></dt><dd><p>The bus connection has been created in a
different process than the current one.</p></dd></dl></div></div><div class="refsect1"><a name="idm47944167100544"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p>The <code class="function">sd_bus_acquire_name()</code> and
<code class="function">sd_bus_release_name()</code> interfaces 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="idm47944167902592"></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_new.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_new</span>(3)</span></a>
</p></div></div></body></html>
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