man/sd_event_loop.html

   1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>sd_event_run</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
   2     a.headerlink {
   3       color: #c60f0f;
   4       font-size: 0.8em;
   5       padding: 0 4px 0 4px;
   6       text-decoration: none;
   7       visibility: hidden;
   8     }
   9
  10     a.headerlink:hover {
  11       background-color: #c60f0f;
  12       color: white;
  13     }
  14
  15     h1:hover > a.headerlink, h2:hover > a.headerlink, h3:hover > a.headerlink, dt:hover > a.headerlink {
  16       visibility: visible;
  17     }
  18   </style><a href="index.html">Index </a>·
  19   <a href="systemd.directives.html">Directives </a>·
  20   <a href="../python-systemd/index.html">Python </a>·
  21   <a href="../libudev/index.html">libudev </a>·
  22   <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 220</span><hr><div class="refentry"><a name="sd_event_run"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_event_run, sd_event_loop — Run libsystemd event loop</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;systemd/sd-event.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_event_run</b>(</code></td><td>sd_event *<var class="pdparam">event</var>, </td></tr><tr><td> </td><td>uint64_t <var class="pdparam">timeout</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_loop</b>(</code></td><td>sd_event *<var class="pdparam">event</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm140674379557392"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_event_run()</code> can be used to run one
  23     iteration of the event loop of libsystemd. This function waits
  24     until an event to process is available and dispatches a handler
  25     for it. Parameter <em class="parameter"><code>timeout</code></em> specifices the
  26     maximum time (in microseconds) to wait. <code class="constant">(uint64_t)
  27     -1</code> may be used to specify an infinite timeout.</p><p><code class="function">sd_event_loop</code> runs
  28     <code class="function">sd_event_wait</code> in a loop with a timeout of
  29     infinity. This makes it suitable for the main event loop of a
  30     program.</p><p>The event loop object <em class="parameter"><code>event</code></em> is
  31     created with
  32     <code class="function">sd_event_new</code>.
  33     Events to wait for and their handlers can be registered with
  34     <code class="function">sd_event_add_time</code>,
  35     <code class="function">sd_event_add_child</code>,
  36     <code class="function">sd_event_add_signal</code>,
  37     <code class="function">sd_event_add_defer</code>,
  38     <code class="function">sd_event_add_exit</code>,
  39     and
  40     <code class="function">sd_event_add_post</code>.
  41     </p><p>For more fine-grained control,
  42     <code class="function">sd_event_prepare</code>,
  43     <code class="function">sd_event_wait</code>, and
  44     <code class="function">sd_event_dispatch</code> may be used. Along with
  45     <code class="function">sd_event_get_fd</code>, those functions make it
  46     possible to integrate the libsystemd loop inside of another event
  47     loop.</p></div><div class="refsect1"><a name="idm140674379544528"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p>On success, these functions return 0 or a positive integer.
  48     On failure, they return a negative errno-style error code.
  49     <code class="function">sd_event_run</code> returns 0 if the event loop is
  50     finished, and a positive value if it can be continued.</p></div><div class="refsect1"><a name="idm140674379542496"></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="-EINVAL"><span class="term"><code class="constant">-EINVAL</code></span><a class="headerlink" title="Permalink to this term" href="#-EINVAL">¶</a></dt><dd><p>Parameter <em class="parameter"><code>event</code></em> is
  51         <code class="constant">NULL</code>.</p></dd><dt id="-EBUSY"><span class="term"><code class="constant">-EBUSY</code></span><a class="headerlink" title="Permalink to this term" href="#-EBUSY">¶</a></dt><dd><p>The event loop object is not in the right
  52         state (see
  53         <a href="sd_event_prepare.html"><span class="citerefentry"><span class="refentrytitle">sd_event_prepare</span>(3)</span></a>
  54         for an explanation of possible states).</p></dd><dt id="-ESTALE"><span class="term"><code class="constant">-ESTALE</code></span><a class="headerlink" title="Permalink to this term" href="#-ESTALE">¶</a></dt><dd><p>The event loop is already terminated.</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 event loop has been created in a different process.</p></dd></dl></div><p>Other errors are possible too.</p></div><div class="refsect1"><a name="idm140674379533168"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p><code class="function">sd_event_run()</code> and
  55     <code class="function">sd_event_loop()</code> are available
  56     as a shared library, which can be compiled and linked to with the
  57     <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>
  58     file.</p></div><div class="refsect1"><a name="idm140674379529392"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
  59       <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
  60       <a href="sd_event_new.html"><span class="citerefentry"><span class="refentrytitle">sd_event_new</span>(3)</span></a>,
  61       <a href="sd_event_wait.html"><span class="citerefentry"><span class="refentrytitle">sd_event_wait</span>(3)</span></a>,
  62       <a href="sd_event_add_io.html"><span class="citerefentry"><span class="refentrytitle">sd_event_add_io</span>(3)</span></a>,
  63       <a href="sd_event_add_time.html"><span class="citerefentry"><span class="refentrytitle">sd_event_add_time</span>(3)</span></a>,
  64       <a href="sd_event_add_signal.html"><span class="citerefentry"><span class="refentrytitle">sd_event_add_signal</span>(3)</span></a>,
  65       <a href="sd_event_add_defer.html"><span class="citerefentry"><span class="refentrytitle">sd_event_add_defer</span>(3)</span></a>,
  66       <a href="sd_event_add_exit.html"><span class="citerefentry"><span class="refentrytitle">sd_event_add_exit</span>(3)</span></a>,
  67       <a href="sd_event_add_post.html"><span class="citerefentry"><span class="refentrytitle">sd_event_add_post</span>(3)</span></a>,
  68       <a class="ulink" href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html" target="_top">GLIb Main Event Loop</a>.
  69     </p></div></div></body></html>