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- <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 21
5</span><hr><div class="refentry"><a name="sd_event_new"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_event_new, sd_event_default, sd_event_ref, sd_event_unref — Acquire and release an event loop object</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_event_new</b>(</code></td><td>sd_bus **<var class="pdparam">event</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_event_default</b>(</code></td><td>sd_bus **<var class="pdparam">event</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_event_ref</b>(</code></td><td>sd_bus *<var class="pdparam">event</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_event_unref</b>(</code></td><td>sd_bus *<var class="pdparam">event</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm214169459136"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_event_new()</code> allocates a new event
+ <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 21
7</span><hr><div class="refentry"><a name="sd_event_new"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_event_new, sd_event_default, sd_event_ref, sd_event_unref — Acquire and release an event loop object</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_event_new</b>(</code></td><td>sd_bus **<var class="pdparam">event</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_event_default</b>(</code></td><td>sd_bus **<var class="pdparam">event</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_event_ref</b>(</code></td><td>sd_bus *<var class="pdparam">event</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_event_unref</b>(</code></td><td>sd_bus *<var class="pdparam">event</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm214176190048"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_event_new()</code> allocates a new event
loop object. The event loop object is returned in the
<em class="parameter"><code>event</code></em> parameter. After use, drop
the returned reference with
<code class="function">sd_event_unref()</code>. When the last reference is
- dropped, the
event loop is freed.</p><p><code class="function">sd_event_default()</code> acquires a reference
+ dropped, the
object is freed.</p><p><code class="function">sd_event_default()</code> acquires a reference
to the default event loop object of the calling thread, possibly
allocating a new object if no default event loop object has been
allocated yet for the thread. After use, drop the returned
recommended to use this call instead of
<code class="function">sd_event_new()</code> in order to share event loop
objects between various components that are dispatched in the same
- thread. All threads either have exactly zero or one default event loop
- associated, but never more.</p><p><code class="function">sd_event_ref()</code> increases the reference
- count
er of the specified event loop object by one.</p><p><code class="function">sd_event_unref()</code> decreases the
- reference counter of the specified event loop object by one. If
- the counter hits zero, the event loop object is freed. Note that it
+ thread. All threads have exactly either zero or one default event loop
+
objects associated, but never more.</p><p><code class="function">sd_event_ref()</code> increases the reference
+ count of the specified event loop object by one.</p><p><code class="function">sd_event_unref()</code> decreases the
+ reference count of the specified event loop object by one. If
+ the count hits zero, the object is freed. Note that it
is freed regardless of whether it is the default event loop object for a
thread or not. This means that allocating an event loop with
<code class="function">sd_event_default()</code>, then releasing it, and
then acquiring a new one with
<code class="function">sd_event_default()</code> will result in two
- distinct objects. Note that, in order to free an event loop object,
+ distinct objects. Note that in order to free an event loop object,
all remaining event sources of the event loop also need to be
- freed as
they each keep a reference to it.</p></div><div class="refsect1"><a name="idm214173348800"></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_event_new()</code> and
+ freed as
each keeps a reference to it.</p></div><div class="refsect1"><a name="idm214176180016"></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_event_new()</code> and
<code class="function">sd_event_default()</code> return 0 or a positive
integer. On failure, they return a negative errno-style error
code. <code class="function">sd_event_ref()</code> always returns a pointer
to the event loop object passed
in. <code class="function">sd_event_unref()</code> always returns
-
NULL.</p></div><div class="refsect1"><a name="idm214173344688"></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>Not enough memory to allocate object</p></dd><dt id="-EMFILE"><span class="term"><code class="varname">-EMFILE</code></span><a class="headerlink" title="Permalink to this term" href="#-EMFILE">¶</a></dt><dd><p>The maximum number of event loops has been allocated.</p></dd></dl></div></div><div class="refsect1"><a name="idm214173340144"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p><code class="function">sd_event_new()</code> and the other functions
+
<code class="constant">NULL</code>.</p></div><div class="refsect1"><a name="idm214180128816"></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>Not enough memory to allocate the object.</p></dd><dt id="-EMFILE"><span class="term"><code class="constant">-EMFILE</code></span><a class="headerlink" title="Permalink to this term" href="#-EMFILE">¶</a></dt><dd><p>The maximum number of event loops has been allocated.</p></dd></dl></div></div><div class="refsect1"><a name="idm214180124320"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p><code class="function">sd_event_new()</code> and the 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="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
- file.</p></div><div class="refsect1"><a name="idm2141
73329680"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
+ <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="idm2141
80120832"></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-event.html"><span class="citerefentry"><span class="refentrytitle">sd-event</span>(3)</span></a>,
<a href="sd_event_add_io.html"><span class="citerefentry"><span class="refentrytitle">sd_event_add_io</span>(3)</span></a>,
projects / systemd.git / blobdiff