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<h1>Module <a href="type_Shutdown.html">Shutdown</a></h1>
<pre><span class="keyword">module</span> Shutdown: <code class="code">sig</code> <a href="Shutdown.html">..</a> <code class="code">end</code></pre><div class="info module top">
<code class="code">shutdown ?force status</code> initiates shutdown, which runs all the <code class="code">at_shutdown</code>
functions, waits for them to finish, and then exits with the supplied status. The
<code class="code">at_shutdown</code> functions can block -- one can use <code class="code">~force</code> to forcibly exit (with
status 1) if the <code class="code">at_shutdown</code> functions do not finish in a reasonable amount of time.
<p>
By default, <code class="code">force</code> is <code class="code">after (sec 10.)</code>.
<p>
Repeated calls to <code class="code">shutdown</code> with the same status will have no effect. Any call to
<code class="code">shutdown</code> with nonzero status will cause that to be the status that is exited with.
A call to <code class="code">shutdown</code> with different nonzero status from the original call will
raise.<br>
</div>
<hr width="100%">
<pre><span id="VALshutdown"><span class="keyword">val</span> shutdown</span> : <code class="type">?force:unit Import.Deferred.t -> int -> unit</code></pre><div class="info ">
<code class="code">shutdown ?force status</code> initiates shutdown, which runs all the <code class="code">at_shutdown</code>
functions, waits for them to finish, and then exits with the supplied status. The
<code class="code">at_shutdown</code> functions can block -- one can use <code class="code">~force</code> to forcibly exit (with
status 1) if the <code class="code">at_shutdown</code> functions do not finish in a reasonable amount of time.
<p>
By default, <code class="code">force</code> is <code class="code">after (sec 10.)</code>.
<p>
Repeated calls to <code class="code">shutdown</code> with the same status will have no effect. Any call to
<code class="code">shutdown</code> with nonzero status will cause that to be the status that is exited with.
A call to <code class="code">shutdown</code> with different nonzero status from the original call will
raise.<br>
</div>
<pre><span id="VALexit"><span class="keyword">val</span> exit</span> : <code class="type">?force:unit Import.Deferred.t -> int -> 'a Import.Deferred.t</code></pre><div class="info ">
<code class="code">exit ?force status</code> is <code class="code">shutdown ?force status; Deferred.never ()</code>.
<p>
We do not have an exit function that returns a non-deferred:
<p>
<pre class="codepre"><code class="code"> val exit : ?force:unit Deferred.t -> int -> _
</code></pre>
<p>
Such a function should not exist, for the same reason that we do not have:
<p>
<pre class="codepre"><code class="code"> val block : 'a Deferred.t -> 'a
</code></pre>
<p>
The semantics of such an exit function would allow one to block a running async job,
and to switch to another one (to run the <code class="code">at_shutdown</code> handlers), without expressing
that switch in the type system via a <code class="code">Deferred.t</code>. That would eliminate all the nice
reasoning guarantees that async gives about concurrent jobs.<br>
</div>
<pre><span id="VALshutting_down"><span class="keyword">val</span> shutting_down</span> : <code class="type">unit -> [ `No | `Yes of int ]</code></pre><div class="info ">
<code class="code">shutting_down ()</code> reports whether we are currently shutting down, and if so, with
what status.<br>
</div>
<pre><span id="VALat_shutdown"><span class="keyword">val</span> at_shutdown</span> : <code class="type">(unit -> unit Import.Deferred.t) -> unit</code></pre><div class="info ">
<code class="code">at_shutdown f</code> causes <code class="code">f ()</code> to be run when <code class="code">shutdown</code> is called, and for <code class="code">shutdown</code>
to wait until the returned deferred finishes.<br>
</div>
<pre><span id="VALdon't_finish_before"><span class="keyword">val</span> don't_finish_before</span> : <code class="type">unit Import.Deferred.t -> unit</code></pre><div class="info ">
<code class="code">don't_finish_before d</code> causes <code class="code">shutdown</code> to wait until <code class="code">d</code> becomes determined before
finishing. It is like <code class="code">at_shutdown (fun _ -> d)</code>, except it is more efficient, and
will not take any space once <code class="code">d</code> is determined. There is a a single <code class="code">at_shutdown</code>
shared among all deferreds supplied to <code class="code">don't_finish_before</code>.<br>
</div>
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