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<h1>
<small class="visible-xs">Elixir v1.7.2</small>
Registry
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L1" title="View Source" class="view-source" rel="help">
<span class="icon-code" aria-hidden="true"></span>
<span class="sr-only">View Source</span>
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</h1>
<section id="moduledoc">
<p>A local, decentralized and scalable key-value process storage.</p>
<p>It allows developers to lookup one or more processes with a given key.
If the registry has <code class="inline">:unique</code> keys, a key points to 0 or 1 processes.
If the registry allows <code class="inline">:duplicate</code> keys, a single key may point to any
number of processes. In both cases, different keys could identify the
same process.</p>
<p>Each entry in the registry is associated to the process that has
registered the key. If the process crashes, the keys associated to that
process are automatically removed. All key comparisons in the registry
are done using the match operation (<a href="Kernel.html#===/2"><code class="inline">===/2</code></a>).</p>
<p>The registry can be used for different purposes, such as name lookups (using
the <code class="inline">:via</code> option), storing properties, custom dispatching rules, or a pubsub
implementation. We explore some of those use cases below.</p>
<p>The registry may also be transparently partitioned, which provides
more scalable behaviour for running registries on highly concurrent
environments with thousands or millions of entries.</p>
<h2 id="module-using-in-via" class="section-heading">
<a href="#module-using-in-via" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Using in <code class="inline">:via</code>
</h2>
<p>Once the registry is started with a given name using
<a href="Registry.html#start_link/1"><code class="inline">Registry.start_link/1</code></a>, it can be used to register and access named
processes using the <code class="inline">{:via, Registry, {registry, key}}</code> tuple:</p>
<pre><code class="nohighlight makeup elixir"><span class="p" data-group-id="3961342762-1">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="3961342762-1">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="3961342762-2">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.ViaTest</span><span class="p" data-group-id="3961342762-2">)</span><span class="w">
</span><span class="n">name</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p" data-group-id="3961342762-3">{</span><span class="ss">:via</span><span class="p">,</span><span class="w"> </span><span class="nc">Registry</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3961342762-4">{</span><span class="nc">Registry.ViaTest</span><span class="p">,</span><span class="w"> </span><span class="s">"agent"</span><span class="p" data-group-id="3961342762-4">}</span><span class="p" data-group-id="3961342762-3">}</span><span class="w">
</span><span class="p" data-group-id="3961342762-5">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="3961342762-5">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Agent</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="3961342762-6">(</span><span class="k" data-group-id="3961342762-7">fn</span><span class="w"> </span><span class="o">-></span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="k" data-group-id="3961342762-7">end</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="n">name</span><span class="p" data-group-id="3961342762-6">)</span><span class="w">
</span><span class="nc">Agent</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="3961342762-8">(</span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="w"> </span><span class="ni">&1</span><span class="p" data-group-id="3961342762-8">)</span><span class="w">
</span><span class="c1">#=> 0</span><span class="w">
</span><span class="nc">Agent</span><span class="o">.</span><span class="n">update</span><span class="p" data-group-id="3961342762-9">(</span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="w"> </span><span class="ni">&1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="3961342762-9">)</span><span class="w">
</span><span class="nc">Agent</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="3961342762-10">(</span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="w"> </span><span class="ni">&1</span><span class="p" data-group-id="3961342762-10">)</span><span class="w">
</span><span class="c1">#=> 1</span></code></pre>
<p>Typically the registry is started as part of a supervision tree though:</p>
<pre><code class="nohighlight makeup elixir"><span class="p" data-group-id="6087890762-1">{</span><span class="nc">Registry</span><span class="p">,</span><span class="w"> </span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.ViaTest</span><span class="p" data-group-id="6087890762-1">}</span></code></pre>
<p>Only registries with unique keys can be used in <code class="inline">:via</code>. If the name is
already taken, the case-specific <code class="inline">start_link</code> function (<a href="Agent.html#start_link/2"><code class="inline">Agent.start_link/2</code></a>
in the example above) will return <code class="inline">{:error, {:already_started, current_pid}}</code>.</p>
<h2 id="module-using-as-a-dispatcher" class="section-heading">
<a href="#module-using-as-a-dispatcher" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Using as a dispatcher
</h2>
<p><a href="Registry.html#content"><code class="inline">Registry</code></a> has a dispatch mechanism that allows developers to implement custom
dispatch logic triggered from the caller. For example, let’s say we have a
duplicate registry started as so:</p>
<pre><code class="nohighlight makeup elixir"><span class="p" data-group-id="4525067533-1">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="4525067533-1">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="4525067533-2">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.DispatcherTest</span><span class="p" data-group-id="4525067533-2">)</span></code></pre>
<p>By calling <a href="#register/3"><code class="inline">register/3</code></a>, different processes can register under a given key
and associate any value under that key. In this case, let’s register the
current process under the key <code class="inline">"hello"</code> and attach the <code class="inline">{IO, :inspect}</code> tuple
to it:</p>
<pre><code class="nohighlight makeup elixir"><span class="p" data-group-id="9995370882-1">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="9995370882-1">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="9995370882-2">(</span><span class="nc">Registry.DispatcherTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9995370882-3">{</span><span class="nc">IO</span><span class="p">,</span><span class="w"> </span><span class="ss">:inspect</span><span class="p" data-group-id="9995370882-3">}</span><span class="p" data-group-id="9995370882-2">)</span></code></pre>
<p>Now, an entity interested in dispatching events for a given key may call
<a href="#dispatch/3"><code class="inline">dispatch/3</code></a> passing in the key and a callback. This callback will be invoked
with a list of all the values registered under the requested key, alongside
the pid of the process that registered each value, in the form of <code class="inline">{pid,
value}</code> tuples. In our example, <code class="inline">value</code> will be the <code class="inline">{module, function}</code> tuple
in the code above:</p>
<pre><code class="nohighlight makeup elixir"><span class="nc">Registry</span><span class="o">.</span><span class="n">dispatch</span><span class="p" data-group-id="0729036221-1">(</span><span class="nc">Registry.DispatcherTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="0729036221-2">fn</span><span class="w"> </span><span class="n">entries</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="k">for</span><span class="w"> </span><span class="p" data-group-id="0729036221-3">{</span><span class="n">pid</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="0729036221-4">{</span><span class="n">module</span><span class="p">,</span><span class="w"> </span><span class="n">function</span><span class="p" data-group-id="0729036221-4">}</span><span class="p" data-group-id="0729036221-3">}</span><span class="w"> </span><span class="o"><-</span><span class="w"> </span><span class="n">entries</span><span class="p">,</span><span class="w"> </span><span class="ss">do</span><span class="p">:</span><span class="w"> </span><span class="n">apply</span><span class="p" data-group-id="0729036221-5">(</span><span class="n">module</span><span class="p">,</span><span class="w"> </span><span class="n">function</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="0729036221-6">[</span><span class="n">pid</span><span class="p" data-group-id="0729036221-6">]</span><span class="p" data-group-id="0729036221-5">)</span><span class="w">
</span><span class="k" data-group-id="0729036221-2">end</span><span class="p" data-group-id="0729036221-1">)</span><span class="w">
</span><span class="c1"># Prints #PID<...> where the pid is for the process that called register/3 above</span><span class="w">
</span><span class="c1">#=> :ok</span></code></pre>
<p>Dispatching happens in the process that calls <a href="#dispatch/3"><code class="inline">dispatch/3</code></a> either serially or
concurrently in case of multiple partitions (via spawned tasks). The
registered processes are not involved in dispatching unless involving them is
done explicitly (for example, by sending them a message in the callback).</p>
<p>Furthermore, if there is a failure when dispatching, due to a bad
registration, dispatching will always fail and the registered process will not
be notified. Therefore let’s make sure we at least wrap and report those
errors:</p>
<pre><code class="nohighlight makeup elixir"><span class="kn">require</span><span class="w"> </span><span class="nc">Logger</span><span class="w">
</span><span class="nc">Registry</span><span class="o">.</span><span class="n">dispatch</span><span class="p" data-group-id="7528145762-1">(</span><span class="nc">Registry.DispatcherTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="7528145762-2">fn</span><span class="w"> </span><span class="n">entries</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="k">for</span><span class="w"> </span><span class="p" data-group-id="7528145762-3">{</span><span class="n">pid</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="7528145762-4">{</span><span class="n">module</span><span class="p">,</span><span class="w"> </span><span class="n">function</span><span class="p" data-group-id="7528145762-4">}</span><span class="p" data-group-id="7528145762-3">}</span><span class="w"> </span><span class="o"><-</span><span class="w"> </span><span class="n">entries</span><span class="w"> </span><span class="k" data-group-id="7528145762-5">do</span><span class="w">
</span><span class="k">try</span><span class="w"> </span><span class="k" data-group-id="7528145762-6">do</span><span class="w">
</span><span class="n">apply</span><span class="p" data-group-id="7528145762-7">(</span><span class="n">module</span><span class="p">,</span><span class="w"> </span><span class="n">function</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="7528145762-8">[</span><span class="n">pid</span><span class="p" data-group-id="7528145762-8">]</span><span class="p" data-group-id="7528145762-7">)</span><span class="w">
</span><span class="k" data-group-id="7528145762-6">catch</span><span class="w">
</span><span class="n">kind</span><span class="p">,</span><span class="w"> </span><span class="n">reason</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="n">formatted</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Exception</span><span class="o">.</span><span class="n">format</span><span class="p" data-group-id="7528145762-9">(</span><span class="n">kind</span><span class="p">,</span><span class="w"> </span><span class="n">reason</span><span class="p">,</span><span class="w"> </span><span class="c">__STACKTRACE__</span><span class="p" data-group-id="7528145762-9">)</span><span class="w">
</span><span class="nc">Logger</span><span class="o">.</span><span class="n">error</span><span class="w"> </span><span class="s">"Registry.dispatch/3 failed with </span><span class="si" data-group-id="7528145762-10">#{</span><span class="n">formatted</span><span class="si" data-group-id="7528145762-10">}</span><span class="s">"</span><span class="w">
</span><span class="k" data-group-id="7528145762-6">end</span><span class="w">
</span><span class="k" data-group-id="7528145762-5">end</span><span class="w">
</span><span class="k" data-group-id="7528145762-2">end</span><span class="p" data-group-id="7528145762-1">)</span><span class="w">
</span><span class="c1"># Prints #PID<...></span><span class="w">
</span><span class="c1">#=> :ok</span></code></pre>
<p>You could also replace the whole <code class="inline">apply</code> system by explicitly sending
messages. That’s the example we will see next.</p>
<h2 id="module-using-as-a-pubsub" class="section-heading">
<a href="#module-using-as-a-pubsub" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Using as a PubSub
</h2>
<p>Registries can also be used to implement a local, non-distributed, scalable
PubSub by relying on the <a href="#dispatch/3"><code class="inline">dispatch/3</code></a> function, similarly to the previous
section: in this case, however, we will send messages to each associated
process, instead of invoking a given module-function.</p>
<p>In this example, we will also set the number of partitions to the number of
schedulers online, which will make the registry more performant on highly
concurrent environments:</p>
<pre><code class="nohighlight makeup elixir"><span class="p" data-group-id="3935473677-1">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="3935473677-1">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="3935473677-2">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.PubSubTest</span><span class="p">,</span><span class="w">
</span><span class="ss">partitions</span><span class="p">:</span><span class="w"> </span><span class="nc">System</span><span class="o">.</span><span class="n">schedulers_online</span><span class="p" data-group-id="3935473677-2">)</span><span class="w">
</span><span class="p" data-group-id="3935473677-3">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="3935473677-3">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="3935473677-4">(</span><span class="nc">Registry.PubSubTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3935473677-5">[</span><span class="p" data-group-id="3935473677-5">]</span><span class="p" data-group-id="3935473677-4">)</span><span class="w">
</span><span class="nc">Registry</span><span class="o">.</span><span class="n">dispatch</span><span class="p" data-group-id="3935473677-6">(</span><span class="nc">Registry.PubSubTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="3935473677-7">fn</span><span class="w"> </span><span class="n">entries</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="k">for</span><span class="w"> </span><span class="p" data-group-id="3935473677-8">{</span><span class="n">pid</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="3935473677-8">}</span><span class="w"> </span><span class="o"><-</span><span class="w"> </span><span class="n">entries</span><span class="p">,</span><span class="w"> </span><span class="ss">do</span><span class="p">:</span><span class="w"> </span><span class="n">send</span><span class="p" data-group-id="3935473677-9">(</span><span class="n">pid</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3935473677-10">{</span><span class="ss">:broadcast</span><span class="p">,</span><span class="w"> </span><span class="s">"world"</span><span class="p" data-group-id="3935473677-10">}</span><span class="p" data-group-id="3935473677-9">)</span><span class="w">
</span><span class="k" data-group-id="3935473677-7">end</span><span class="p" data-group-id="3935473677-6">)</span><span class="w">
</span><span class="c1">#=> :ok</span></code></pre>
<p>The example above broadcasted the message <code class="inline">{:broadcast, "world"}</code> to all
processes registered under the “topic” (or “key” as we called it until now)
<code class="inline">"hello"</code>.</p>
<p>The third argument given to <a href="#register/3"><code class="inline">register/3</code></a> is a value associated to the
current process. While in the previous section we used it when dispatching,
in this particular example we are not interested in it, so we have set it
to an empty list. You could store a more meaningful value if necessary.</p>
<h2 id="module-registrations" class="section-heading">
<a href="#module-registrations" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Registrations
</h2>
<p>Looking up, dispatching and registering are efficient and immediate at
the cost of delayed unsubscription. For example, if a process crashes,
its keys are automatically removed from the registry but the change may
not propagate immediately. This means certain operations may return processes
that are already dead. When such may happen, it will be explicitly stated
in the function documentation.</p>
<p>However, keep in mind those cases are typically not an issue. After all, a
process referenced by a pid may crash at any time, including between getting
the value from the registry and sending it a message. Many parts of the standard
library are designed to cope with that, such as <a href="Process.html#monitor/1"><code class="inline">Process.monitor/1</code></a> which will
deliver the <code class="inline">:DOWN</code> message immediately if the monitored process is already dead
and <a href="Kernel.html#send/2"><code class="inline">Kernel.send/2</code></a> which acts as a no-op for dead processes.</p>
<h2 id="module-ets" class="section-heading">
<a href="#module-ets" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
ETS
</h2>
<p>Note that the registry uses one ETS table plus two ETS tables per partition.</p>
</section>
<section id="summary" class="details-list">
<h1 class="section-heading">
<a class="hover-link" href="#summary">
<span class="icon-link" aria-hidden="true"></span>
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Summary
</h1>
<div class="summary-types summary">
<h2>
<a href="#types">Types</a>
</h2>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:guard/0">guard()</a>
</div>
<div class="summary-synopsis"><p>A guard to be evaluated when matching on objects in a registry</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:guards/0">guards()</a>
</div>
<div class="summary-synopsis"><p>A list of guards to be evaluated when matching on objects in a registry</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:key/0">key()</a>
</div>
<div class="summary-synopsis"><p>The type of keys allowed on registration</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:keys/0">keys()</a>
</div>
<div class="summary-synopsis"><p>The type of the registry</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:match_pattern/0">match_pattern()</a>
</div>
<div class="summary-synopsis"><p>A pattern to match on objects in a registry</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:meta_key/0">meta_key()</a>
</div>
<div class="summary-synopsis"><p>The type of registry metadata keys</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:meta_value/0">meta_value()</a>
</div>
<div class="summary-synopsis"><p>The type of registry metadata values</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:registry/0">registry()</a>
</div>
<div class="summary-synopsis"><p>The registry identifier</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:value/0">value()</a>
</div>
<div class="summary-synopsis"><p>The type of values allowed on registration</p>
</div>
</div>
</div>
<div class="summary-functions summary">
<h2>
<a href="#functions">Functions</a>
</h2>
<div class="summary-row">
<div class="summary-signature">
<a href="#child_spec/1">child_spec(opts)</a>
</div>
<div class="summary-synopsis"><p>Returns a specification to start a registry under a supervisor</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#count/1">count(registry)</a>
</div>
<div class="summary-synopsis"><p>Returns the number of registered keys in a registry.
It runs in constant time</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#count_match/4">count_match(registry, key, pattern, guards \\ [])</a>
</div>
<div class="summary-synopsis"><p>Returns the number of <code class="inline">{pid, value}</code> pairs under the given <code class="inline">key</code> in <code class="inline">registry</code>
that match <code class="inline">pattern</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#dispatch/4">dispatch(registry, key, mfa_or_fun, opts \\ [])</a>
</div>
<div class="summary-synopsis"><p>Invokes the callback with all entries under <code class="inline">key</code> in each partition
for the given <code class="inline">registry</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#keys/2">keys(registry, pid)</a>
</div>
<div class="summary-synopsis"><p>Returns the known keys for the given <code class="inline">pid</code> in <code class="inline">registry</code> in no particular order</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#lookup/2">lookup(registry, key)</a>
</div>
<div class="summary-synopsis"><p>Finds the <code class="inline">{pid, value}</code> pair for the given <code class="inline">key</code> in <code class="inline">registry</code> in no particular order</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#match/4">match(registry, key, pattern, guards \\ [])</a>
</div>
<div class="summary-synopsis"><p>Returns <code class="inline">{pid, value}</code> pairs under the given <code class="inline">key</code> in <code class="inline">registry</code> that match <code class="inline">pattern</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#meta/2">meta(registry, key)</a>
</div>
<div class="summary-synopsis"><p>Reads registry metadata given on <code class="inline">start_link/3</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#put_meta/3">put_meta(registry, key, value)</a>
</div>
<div class="summary-synopsis"><p>Stores registry metadata</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#register/3">register(registry, key, value)</a>
</div>
<div class="summary-synopsis"><p>Registers the current process under the given <code class="inline">key</code> in <code class="inline">registry</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#start_link/1">start_link(options)</a>
</div>
<div class="summary-synopsis"><p>Starts the registry as a supervisor process</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#unregister/2">unregister(registry, key)</a>
</div>
<div class="summary-synopsis"><p>Unregisters all entries for the given <code class="inline">key</code> associated to the current
process in <code class="inline">registry</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#unregister_match/4">unregister_match(registry, key, pattern, guards \\ [])</a>
</div>
<div class="summary-synopsis"><p>Unregister entries for a given key matching a pattern</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#update_value/3">update_value(registry, key, callback)</a>
</div>
<div class="summary-synopsis"><p>Updates the value for <code class="inline">key</code> for the current process in the unique <code class="inline">registry</code></p>
</div>
</div>
</div>
</section>
<section id="types" class="details-list">
<h1 class="section-heading">
<a class="hover-link" href="#types">
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Types
</h1>
<div class="types-list">
<div class="detail" id="t:guard/0">
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<span class="signature">guard()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L178" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>guard() :: {<a href="typespecs.html#basic-types">atom</a>() | <a href="typespecs.html#built-in-types">term</a>()}</pre>
</div>
</div>
<section class="docstring">
<p>A guard to be evaluated when matching on objects in a registry</p>
</section>
</div>
<div class="detail" id="t:guards/0">
<div class="detail-header">
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<span class="signature">guards()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L181" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>guards() :: [<a href="#t:guard/0">guard</a>()] | []</pre>
</div>
</div>
<section class="docstring">
<p>A list of guards to be evaluated when matching on objects in a registry</p>
</section>
</div>
<div class="detail" id="t:key/0">
<div class="detail-header">
<a href="#t:key/0" class="detail-link" title="Link to this type">
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<span class="signature">key()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L163" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>key() :: <a href="typespecs.html#built-in-types">term</a>()</pre>
</div>
</div>
<section class="docstring">
<p>The type of keys allowed on registration</p>
</section>
</div>
<div class="detail" id="t:keys/0">
<div class="detail-header">
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<span class="signature">keys()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L160" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>keys() :: :unique | :duplicate</pre>
</div>
</div>
<section class="docstring">
<p>The type of the registry</p>
</section>
</div>
<div class="detail" id="t:match_pattern/0">
<div class="detail-header">
<a href="#t:match_pattern/0" class="detail-link" title="Link to this type">
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<span class="signature">match_pattern()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L175" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>match_pattern() :: <a href="typespecs.html#basic-types">atom</a>() | <a href="typespecs.html#built-in-types">term</a>()</pre>
</div>
</div>
<section class="docstring">
<p>A pattern to match on objects in a registry</p>
</section>
</div>
<div class="detail" id="t:meta_key/0">
<div class="detail-header">
<a href="#t:meta_key/0" class="detail-link" title="Link to this type">
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<span class="signature">meta_key()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L169" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
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</a>
<div class="specs">
<pre>meta_key() :: <a href="typespecs.html#basic-types">atom</a>() | <a href="typespecs.html#basic-types">tuple</a>()</pre>
</div>
</div>
<section class="docstring">
<p>The type of registry metadata keys</p>
</section>
</div>
<div class="detail" id="t:meta_value/0">
<div class="detail-header">
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<span class="signature">meta_value()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L172" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>meta_value() :: <a href="typespecs.html#built-in-types">term</a>()</pre>
</div>
</div>
<section class="docstring">
<p>The type of registry metadata values</p>
</section>
</div>
<div class="detail" id="t:registry/0">
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<a href="#t:registry/0" class="detail-link" title="Link to this type">
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<span class="signature">registry()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L157" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>registry() :: <a href="typespecs.html#basic-types">atom</a>()</pre>
</div>
</div>
<section class="docstring">
<p>The registry identifier</p>
</section>
</div>
<div class="detail" id="t:value/0">
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<span class="signature">value()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L166" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>value() :: <a href="typespecs.html#built-in-types">term</a>()</pre>
</div>
</div>
<section class="docstring">
<p>The type of values allowed on registration</p>
</section>
</div>
</div>
</section>
<section id="functions" class="details-list">
<h1 class="section-heading">
<a class="hover-link" href="#functions">
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Functions
</h1>
<div class="detail" id="child_spec/1">
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<span class="signature">child_spec(opts)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L339" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.5.0)</span>
</div>
<section class="docstring">
<p>Returns a specification to start a registry under a supervisor.</p>
<p>See <a href="Supervisor.html"><code class="inline">Supervisor</code></a>.</p>
</section>
</div>
<div class="detail" id="count/1">
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<span class="signature">count(registry)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L1018" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.7.0)</span>
<div class="specs">
<pre>count(<a href="#t:registry/0">registry</a>()) :: <a href="typespecs.html#basic-types">non_neg_integer</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Returns the number of registered keys in a registry.
It runs in constant time.</p>
<h2 id="count/1-examples" class="section-heading">
<a href="#count/1-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>In the example below we register the current process and ask for the
number of keys in the registry:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="9976149527-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.UniqueCountTest</span><span class="p" data-group-id="9976149527-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count</span><span class="p" data-group-id="9976149527-2">(</span><span class="nc">Registry.UniqueCountTest</span><span class="p" data-group-id="9976149527-2">)</span><span class="w">
</span><span class="mi">0</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="9976149527-3">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="9976149527-3">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="9976149527-4">(</span><span class="nc">Registry.UniqueCountTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="9976149527-4">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="9976149527-5">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="9976149527-5">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="9976149527-6">(</span><span class="nc">Registry.UniqueCountTest</span><span class="p">,</span><span class="w"> </span><span class="s">"world"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="9976149527-6">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count</span><span class="p" data-group-id="9976149527-7">(</span><span class="nc">Registry.UniqueCountTest</span><span class="p" data-group-id="9976149527-7">)</span><span class="w">
</span><span class="mi">2</span></code></pre>
<p>The same applies to duplicate registries:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="6669746768-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.DuplicateCountTest</span><span class="p" data-group-id="6669746768-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count</span><span class="p" data-group-id="6669746768-2">(</span><span class="nc">Registry.DuplicateCountTest</span><span class="p" data-group-id="6669746768-2">)</span><span class="w">
</span><span class="mi">0</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="6669746768-3">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="6669746768-3">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="6669746768-4">(</span><span class="nc">Registry.DuplicateCountTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="6669746768-4">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="6669746768-5">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="6669746768-5">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="6669746768-6">(</span><span class="nc">Registry.DuplicateCountTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="6669746768-6">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count</span><span class="p" data-group-id="6669746768-7">(</span><span class="nc">Registry.DuplicateCountTest</span><span class="p" data-group-id="6669746768-7">)</span><span class="w">
</span><span class="mi">2</span></code></pre>
</section>
</div>
<div class="detail" id="count_match/4">
<span id="count_match/3"></span>
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<span class="signature">count_match(registry, key, pattern, guards \\ [])</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L1082" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.7.0)</span>
<div class="specs">
<pre>count_match(<a href="#t:registry/0">registry</a>(), <a href="#t:key/0">key</a>(), <a href="#t:match_pattern/0">match_pattern</a>(), <a href="#t:guards/0">guards</a>()) :: <a href="typespecs.html#basic-types">non_neg_integer</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Returns the number of <code class="inline">{pid, value}</code> pairs under the given <code class="inline">key</code> in <code class="inline">registry</code>
that match <code class="inline">pattern</code>.</p>
<p>Pattern must be an atom or a tuple that will match the structure of the
value stored in the registry. The atom <code class="inline">:_</code> can be used to ignore a given
value or tuple element, while the atom <code class="inline">:"$1"</code> can be used to temporarily assign part
of pattern to a variable for a subsequent comparison.</p>
<p>Optionally, it is possible to pass a list of guard conditions for more precise matching.
Each guard is a tuple, which describes checks that should be passed by assigned part of pattern.
For example the <code class="inline">$1 > 1</code> guard condition would be expressed as the <code class="inline">{:>, :"$1", 1}</code> tuple.
Please note that guard conditions will work only for assigned variables like <code class="inline">:"$1"</code>, <code class="inline">:"$2"</code>, etc.
Avoid usage of special match variables <code class="inline">:"$_"</code> and <code class="inline">:"$$"</code>, because it might not work as expected.</p>
<p>Zero will be returned if there is no match.</p>
<p>For unique registries, a single partition lookup is necessary. For
duplicate registries, all partitions must be looked up.</p>
<h2 id="count_match/4-examples" class="section-heading">
<a href="#count_match/4-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>In the example below we register the current process under the same
key in a duplicate registry but with different values:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="9302126957-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.MatchTest</span><span class="p" data-group-id="9302126957-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="9302126957-2">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="9302126957-2">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="9302126957-3">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-4">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="9302126957-4">}</span><span class="p" data-group-id="9302126957-3">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="9302126957-5">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="9302126957-5">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="9302126957-6">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-7">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="9302126957-7">}</span><span class="p" data-group-id="9302126957-6">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count_match</span><span class="p" data-group-id="9302126957-8">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-9">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="9302126957-9">}</span><span class="p" data-group-id="9302126957-8">)</span><span class="w">
</span><span class="mi">1</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count_match</span><span class="p" data-group-id="9302126957-10">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-11">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="9302126957-11">}</span><span class="p" data-group-id="9302126957-10">)</span><span class="w">
</span><span class="mi">1</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count_match</span><span class="p" data-group-id="9302126957-12">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-13">{</span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="9302126957-13">}</span><span class="p" data-group-id="9302126957-12">)</span><span class="w">
</span><span class="mi">2</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count_match</span><span class="p" data-group-id="9302126957-14">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-15">{</span><span class="ss">:"$1"</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p" data-group-id="9302126957-15">}</span><span class="p" data-group-id="9302126957-14">)</span><span class="w">
</span><span class="mi">2</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count_match</span><span class="p" data-group-id="9302126957-16">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-17">{</span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p" data-group-id="9302126957-17">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-18">[</span><span class="p" data-group-id="9302126957-19">{</span><span class="ss">:></span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="9302126957-19">}</span><span class="p" data-group-id="9302126957-18">]</span><span class="p" data-group-id="9302126957-16">)</span><span class="w">
</span><span class="mi">1</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">count_match</span><span class="p" data-group-id="9302126957-20">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-21">{</span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="9302126957-21">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9302126957-22">[</span><span class="p" data-group-id="9302126957-23">{</span><span class="ss">:is_atom</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p" data-group-id="9302126957-23">}</span><span class="p" data-group-id="9302126957-22">]</span><span class="p" data-group-id="9302126957-20">)</span><span class="w">
</span><span class="mi">2</span></code></pre>
</section>
</div>
<div class="detail" id="dispatch/4">
<span id="dispatch/3"></span>
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<a href="#dispatch/4" class="detail-link" title="Link to this function">
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</a>
<span class="signature">dispatch(registry, key, mfa_or_fun, opts \\ [])</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L414" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>dispatch(<a href="#t:registry/0">registry</a>(), <a href="#t:key/0">key</a>(), dispatcher, <a href="typespecs.html#built-in-types">keyword</a>()) :: :ok
when dispatcher:
(entries :: [{<a href="typespecs.html#basic-types">pid</a>(), <a href="#t:value/0">value</a>()}] -> <a href="typespecs.html#built-in-types">term</a>()) | {<a href="typespecs.html#built-in-types">module</a>(), <a href="typespecs.html#basic-types">atom</a>(), [<a href="typespecs.html#basic-types">any</a>()]}</pre>
</div>
</div>
<section class="docstring">
<p>Invokes the callback with all entries under <code class="inline">key</code> in each partition
for the given <code class="inline">registry</code>.</p>
<p>The list of <code class="inline">entries</code> is a non-empty list of two-element tuples where
the first element is the pid and the second element is the value
associated to the pid. If there are no entries for the given key,
the callback is never invoked.</p>
<p>If the registry is partitioned, the callback is invoked multiple times
per partition. If the registry is partitioned and <code class="inline">parallel: true</code> is
given as an option, the dispatching happens in parallel. In both cases,
the callback is only invoked if there are entries for that partition.</p>
<p>See the module documentation for examples of using the <a href="#dispatch/3"><code class="inline">dispatch/3</code></a>
function for building custom dispatching or a pubsub system.</p>
</section>
</div>
<div class="detail" id="keys/2">
<div class="detail-header">
<a href="#keys/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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</a>
<span class="signature">keys(registry, pid)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L647" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>keys(<a href="#t:registry/0">registry</a>(), <a href="typespecs.html#basic-types">pid</a>()) :: [<a href="#t:key/0">key</a>()]</pre>
</div>
</div>
<section class="docstring">
<p>Returns the known keys for the given <code class="inline">pid</code> in <code class="inline">registry</code> in no particular order.</p>
<p>If the registry is unique, the keys are unique. Otherwise
they may contain duplicates if the process was registered
under the same key multiple times. The list will be empty
if the process is dead or it has no keys in this registry.</p>
<h2 id="keys/2-examples" class="section-heading">
<a href="#keys/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>Registering under a unique registry does not allow multiple entries:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="4955673203-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.UniqueKeysTest</span><span class="p" data-group-id="4955673203-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="4955673203-2">(</span><span class="nc">Registry.UniqueKeysTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4955673203-3">(</span><span class="p" data-group-id="4955673203-3">)</span><span class="p" data-group-id="4955673203-2">)</span><span class="w">
</span><span class="p" data-group-id="4955673203-4">[</span><span class="p" data-group-id="4955673203-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="4955673203-5">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="4955673203-5">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4955673203-6">(</span><span class="nc">Registry.UniqueKeysTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="4955673203-6">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4955673203-7">(</span><span class="nc">Registry.UniqueKeysTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:later</span><span class="p" data-group-id="4955673203-7">)</span><span class="w"> </span><span class="c1"># registry is :unique</span><span class="w">
</span><span class="p" data-group-id="4955673203-8">{</span><span class="ss">:error</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="4955673203-9">{</span><span class="ss">:already_registered</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4955673203-10">(</span><span class="p" data-group-id="4955673203-10">)</span><span class="p" data-group-id="4955673203-9">}</span><span class="p" data-group-id="4955673203-8">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="4955673203-11">(</span><span class="nc">Registry.UniqueKeysTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4955673203-12">(</span><span class="p" data-group-id="4955673203-12">)</span><span class="p" data-group-id="4955673203-11">)</span><span class="w">
</span><span class="p" data-group-id="4955673203-13">[</span><span class="s">"hello"</span><span class="p" data-group-id="4955673203-13">]</span></code></pre>
<p>Such is possible for duplicate registries though:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="4969566711-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.DuplicateKeysTest</span><span class="p" data-group-id="4969566711-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="4969566711-2">(</span><span class="nc">Registry.DuplicateKeysTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4969566711-3">(</span><span class="p" data-group-id="4969566711-3">)</span><span class="p" data-group-id="4969566711-2">)</span><span class="w">
</span><span class="p" data-group-id="4969566711-4">[</span><span class="p" data-group-id="4969566711-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="4969566711-5">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="4969566711-5">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4969566711-6">(</span><span class="nc">Registry.DuplicateKeysTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="4969566711-6">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="4969566711-7">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="4969566711-7">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4969566711-8">(</span><span class="nc">Registry.DuplicateKeysTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="4969566711-8">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="4969566711-9">(</span><span class="nc">Registry.DuplicateKeysTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4969566711-10">(</span><span class="p" data-group-id="4969566711-10">)</span><span class="p" data-group-id="4969566711-9">)</span><span class="w">
</span><span class="p" data-group-id="4969566711-11">[</span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="4969566711-11">]</span></code></pre>
</section>
</div>
<div class="detail" id="lookup/2">
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<span class="signature">lookup(registry, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L528" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>lookup(<a href="#t:registry/0">registry</a>(), <a href="#t:key/0">key</a>()) :: [{<a href="typespecs.html#basic-types">pid</a>(), <a href="#t:value/0">value</a>()}]</pre>
</div>
</div>
<section class="docstring">
<p>Finds the <code class="inline">{pid, value}</code> pair for the given <code class="inline">key</code> in <code class="inline">registry</code> in no particular order.</p>
<p>An empty list if there is no match.</p>
<p>For unique registries, a single partition lookup is necessary. For
duplicate registries, all partitions must be looked up.</p>
<h2 id="lookup/2-examples" class="section-heading">
<a href="#lookup/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>In the example below we register the current process and look it up
both from itself and other processes:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="6316099563-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.UniqueLookupTest</span><span class="p" data-group-id="6316099563-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="6316099563-2">(</span><span class="nc">Registry.UniqueLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="6316099563-2">)</span><span class="w">
</span><span class="p" data-group-id="6316099563-3">[</span><span class="p" data-group-id="6316099563-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="6316099563-4">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="6316099563-4">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="6316099563-5">(</span><span class="nc">Registry.UniqueLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="6316099563-5">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="6316099563-6">(</span><span class="nc">Registry.UniqueLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="6316099563-6">)</span><span class="w">
</span><span class="p" data-group-id="6316099563-7">[</span><span class="p" data-group-id="6316099563-8">{</span><span class="n">self</span><span class="p" data-group-id="6316099563-9">(</span><span class="p" data-group-id="6316099563-9">)</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="6316099563-8">}</span><span class="p" data-group-id="6316099563-7">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Task</span><span class="o">.</span><span class="n">async</span><span class="p" data-group-id="6316099563-10">(</span><span class="k" data-group-id="6316099563-11">fn</span><span class="w"> </span><span class="o">-></span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="6316099563-12">(</span><span class="nc">Registry.UniqueLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="6316099563-12">)</span><span class="w"> </span><span class="k" data-group-id="6316099563-11">end</span><span class="p" data-group-id="6316099563-10">)</span><span class="w"> </span><span class="o">|></span><span class="w"> </span><span class="nc">Task</span><span class="o">.</span><span class="n">await</span><span class="p" data-group-id="6316099563-13">(</span><span class="p" data-group-id="6316099563-13">)</span><span class="w">
</span><span class="p" data-group-id="6316099563-14">[</span><span class="p" data-group-id="6316099563-15">{</span><span class="n">self</span><span class="p" data-group-id="6316099563-16">(</span><span class="p" data-group-id="6316099563-16">)</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="6316099563-15">}</span><span class="p" data-group-id="6316099563-14">]</span></code></pre>
<p>The same applies to duplicate registries:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="3469556279-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.DuplicateLookupTest</span><span class="p" data-group-id="3469556279-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="3469556279-2">(</span><span class="nc">Registry.DuplicateLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="3469556279-2">)</span><span class="w">
</span><span class="p" data-group-id="3469556279-3">[</span><span class="p" data-group-id="3469556279-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="3469556279-4">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="3469556279-4">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="3469556279-5">(</span><span class="nc">Registry.DuplicateLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="3469556279-5">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="3469556279-6">(</span><span class="nc">Registry.DuplicateLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="3469556279-6">)</span><span class="w">
</span><span class="p" data-group-id="3469556279-7">[</span><span class="p" data-group-id="3469556279-8">{</span><span class="n">self</span><span class="p" data-group-id="3469556279-9">(</span><span class="p" data-group-id="3469556279-9">)</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="3469556279-8">}</span><span class="p" data-group-id="3469556279-7">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="3469556279-10">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="3469556279-10">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="3469556279-11">(</span><span class="nc">Registry.DuplicateLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:another</span><span class="p" data-group-id="3469556279-11">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Enum</span><span class="o">.</span><span class="n">sort</span><span class="p" data-group-id="3469556279-12">(</span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="3469556279-13">(</span><span class="nc">Registry.DuplicateLookupTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="3469556279-13">)</span><span class="p" data-group-id="3469556279-12">)</span><span class="w">
</span><span class="p" data-group-id="3469556279-14">[</span><span class="p" data-group-id="3469556279-15">{</span><span class="n">self</span><span class="p" data-group-id="3469556279-16">(</span><span class="p" data-group-id="3469556279-16">)</span><span class="p">,</span><span class="w"> </span><span class="ss">:another</span><span class="p" data-group-id="3469556279-15">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3469556279-17">{</span><span class="n">self</span><span class="p" data-group-id="3469556279-18">(</span><span class="p" data-group-id="3469556279-18">)</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="3469556279-17">}</span><span class="p" data-group-id="3469556279-14">]</span></code></pre>
</section>
</div>
<div class="detail" id="match/4">
<span id="match/3"></span>
<div class="detail-header">
<a href="#match/4" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
<span class="sr-only">Link to this function</span>
</a>
<span class="signature">match(registry, key, pattern, guards \\ [])</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L594" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>match(<a href="#t:registry/0">registry</a>(), <a href="#t:key/0">key</a>(), <a href="#t:match_pattern/0">match_pattern</a>(), <a href="#t:guards/0">guards</a>()) :: [{<a href="typespecs.html#basic-types">pid</a>(), <a href="typespecs.html#built-in-types">term</a>()}]</pre>
</div>
</div>
<section class="docstring">
<p>Returns <code class="inline">{pid, value}</code> pairs under the given <code class="inline">key</code> in <code class="inline">registry</code> that match <code class="inline">pattern</code>.</p>
<p>Pattern must be an atom or a tuple that will match the structure of the
value stored in the registry. The atom <code class="inline">:_</code> can be used to ignore a given
value or tuple element, while the atom <code class="inline">:"$1"</code> can be used to temporarily assign part
of pattern to a variable for a subsequent comparison.</p>
<p>Optionally, it is possible to pass a list of guard conditions for more precise matching.
Each guard is a tuple, which describes checks that should be passed by assigned part of pattern.
For example the <code class="inline">$1 > 1</code> guard condition would be expressed as the <code class="inline">{:>, :"$1", 1}</code> tuple.
Please note that guard conditions will work only for assigned variables like <code class="inline">:"$1"</code>, <code class="inline">:"$2"</code>, etc.
Avoid usage of special match variables <code class="inline">:"$_"</code> and <code class="inline">:"$$"</code>, because it might not work as expected.</p>
<p>An empty list will be returned if there is no match.</p>
<p>For unique registries, a single partition lookup is necessary. For
duplicate registries, all partitions must be looked up.</p>
<h2 id="match/4-examples" class="section-heading">
<a href="#match/4-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>In the example below we register the current process under the same
key in a duplicate registry but with different values:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="6474016409-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.MatchTest</span><span class="p" data-group-id="6474016409-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="6474016409-2">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="6474016409-2">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="6474016409-3">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-4">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6474016409-4">}</span><span class="p" data-group-id="6474016409-3">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="6474016409-5">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="6474016409-5">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="6474016409-6">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-7">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6474016409-7">}</span><span class="p" data-group-id="6474016409-6">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">match</span><span class="p" data-group-id="6474016409-8">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-9">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="6474016409-9">}</span><span class="p" data-group-id="6474016409-8">)</span><span class="w">
</span><span class="p" data-group-id="6474016409-10">[</span><span class="p" data-group-id="6474016409-11">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-12">(</span><span class="p" data-group-id="6474016409-12">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-13">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6474016409-13">}</span><span class="p" data-group-id="6474016409-11">}</span><span class="p" data-group-id="6474016409-10">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">match</span><span class="p" data-group-id="6474016409-14">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-15">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="6474016409-15">}</span><span class="p" data-group-id="6474016409-14">)</span><span class="w">
</span><span class="p" data-group-id="6474016409-16">[</span><span class="p" data-group-id="6474016409-17">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-18">(</span><span class="p" data-group-id="6474016409-18">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-19">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6474016409-19">}</span><span class="p" data-group-id="6474016409-17">}</span><span class="p" data-group-id="6474016409-16">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">match</span><span class="p" data-group-id="6474016409-20">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-21">{</span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="6474016409-21">}</span><span class="p" data-group-id="6474016409-20">)</span><span class="w"> </span><span class="o">|></span><span class="w"> </span><span class="nc">Enum</span><span class="o">.</span><span class="n">sort</span><span class="p" data-group-id="6474016409-22">(</span><span class="p" data-group-id="6474016409-22">)</span><span class="w">
</span><span class="p" data-group-id="6474016409-23">[</span><span class="p" data-group-id="6474016409-24">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-25">(</span><span class="p" data-group-id="6474016409-25">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-26">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6474016409-26">}</span><span class="p" data-group-id="6474016409-24">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-27">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-28">(</span><span class="p" data-group-id="6474016409-28">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-29">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6474016409-29">}</span><span class="p" data-group-id="6474016409-27">}</span><span class="p" data-group-id="6474016409-23">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">match</span><span class="p" data-group-id="6474016409-30">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-31">{</span><span class="ss">:"$1"</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p" data-group-id="6474016409-31">}</span><span class="p" data-group-id="6474016409-30">)</span><span class="w"> </span><span class="o">|></span><span class="w"> </span><span class="nc">Enum</span><span class="o">.</span><span class="n">sort</span><span class="p" data-group-id="6474016409-32">(</span><span class="p" data-group-id="6474016409-32">)</span><span class="w">
</span><span class="p" data-group-id="6474016409-33">[</span><span class="p" data-group-id="6474016409-34">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-35">(</span><span class="p" data-group-id="6474016409-35">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-36">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6474016409-36">}</span><span class="p" data-group-id="6474016409-34">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-37">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-38">(</span><span class="p" data-group-id="6474016409-38">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-39">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6474016409-39">}</span><span class="p" data-group-id="6474016409-37">}</span><span class="p" data-group-id="6474016409-33">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">match</span><span class="p" data-group-id="6474016409-40">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-41">{</span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p" data-group-id="6474016409-41">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-42">[</span><span class="p" data-group-id="6474016409-43">{</span><span class="ss">:></span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6474016409-43">}</span><span class="p" data-group-id="6474016409-42">]</span><span class="p" data-group-id="6474016409-40">)</span><span class="w">
</span><span class="p" data-group-id="6474016409-44">[</span><span class="p" data-group-id="6474016409-45">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-46">(</span><span class="p" data-group-id="6474016409-46">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-47">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6474016409-47">}</span><span class="p" data-group-id="6474016409-45">}</span><span class="p" data-group-id="6474016409-44">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">match</span><span class="p" data-group-id="6474016409-48">(</span><span class="nc">Registry.MatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-49">{</span><span class="ss">:_</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p">,</span><span class="w"> </span><span class="ss">:_</span><span class="p" data-group-id="6474016409-49">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-50">[</span><span class="p" data-group-id="6474016409-51">{</span><span class="ss">:is_atom</span><span class="p">,</span><span class="w"> </span><span class="ss">:"$1"</span><span class="p" data-group-id="6474016409-51">}</span><span class="p" data-group-id="6474016409-50">]</span><span class="p" data-group-id="6474016409-48">)</span><span class="w"> </span><span class="o">|></span><span class="w"> </span><span class="nc">Enum</span><span class="o">.</span><span class="n">sort</span><span class="p" data-group-id="6474016409-52">(</span><span class="p" data-group-id="6474016409-52">)</span><span class="w">
</span><span class="p" data-group-id="6474016409-53">[</span><span class="p" data-group-id="6474016409-54">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-55">(</span><span class="p" data-group-id="6474016409-55">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-56">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6474016409-56">}</span><span class="p" data-group-id="6474016409-54">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-57">{</span><span class="n">self</span><span class="p" data-group-id="6474016409-58">(</span><span class="p" data-group-id="6474016409-58">)</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6474016409-59">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">:atom</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6474016409-59">}</span><span class="p" data-group-id="6474016409-57">}</span><span class="p" data-group-id="6474016409-53">]</span></code></pre>
</section>
</div>
<div class="detail" id="meta/2">
<div class="detail-header">
<a href="#meta/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
<span class="sr-only">Link to this function</span>
</a>
<span class="signature">meta(registry, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L947" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
<span class="sr-only">View Source</span>
</a>
<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>meta(<a href="#t:registry/0">registry</a>(), <a href="#t:meta_key/0">meta_key</a>()) :: {:ok, <a href="#t:meta_value/0">meta_value</a>()} | :error</pre>
</div>
</div>
<section class="docstring">
<p>Reads registry metadata given on <code class="inline">start_link/3</code>.</p>
<p>Atoms and tuples are allowed as keys.</p>
<h2 id="meta/2-examples" class="section-heading">
<a href="#meta/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="0658839653-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.MetaTest</span><span class="p">,</span><span class="w"> </span><span class="ss">meta</span><span class="p">:</span><span class="w"> </span><span class="p" data-group-id="0658839653-2">[</span><span class="ss">custom_key</span><span class="p">:</span><span class="w"> </span><span class="s">"custom_value"</span><span class="p" data-group-id="0658839653-2">]</span><span class="p" data-group-id="0658839653-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">meta</span><span class="p" data-group-id="0658839653-3">(</span><span class="nc">Registry.MetaTest</span><span class="p">,</span><span class="w"> </span><span class="ss">:custom_key</span><span class="p" data-group-id="0658839653-3">)</span><span class="w">
</span><span class="p" data-group-id="0658839653-4">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="s">"custom_value"</span><span class="p" data-group-id="0658839653-4">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">meta</span><span class="p" data-group-id="0658839653-5">(</span><span class="nc">Registry.MetaTest</span><span class="p">,</span><span class="w"> </span><span class="ss">:unknown_key</span><span class="p" data-group-id="0658839653-5">)</span><span class="w">
</span><span class="ss">:error</span></code></pre>
</section>
</div>
<div class="detail" id="put_meta/3">
<div class="detail-header">
<a href="#put_meta/3" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
<span class="sr-only">Link to this function</span>
</a>
<span class="signature">put_meta(registry, key, value)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L979" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
<span class="sr-only">View Source</span>
</a>
<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>put_meta(<a href="#t:registry/0">registry</a>(), <a href="#t:meta_key/0">meta_key</a>(), <a href="#t:meta_value/0">meta_value</a>()) :: :ok</pre>
</div>
</div>
<section class="docstring">
<p>Stores registry metadata.</p>
<p>Atoms and tuples are allowed as keys.</p>
<h2 id="put_meta/3-examples" class="section-heading">
<a href="#put_meta/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="1619136303-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.PutMetaTest</span><span class="p" data-group-id="1619136303-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">put_meta</span><span class="p" data-group-id="1619136303-2">(</span><span class="nc">Registry.PutMetaTest</span><span class="p">,</span><span class="w"> </span><span class="ss">:custom_key</span><span class="p">,</span><span class="w"> </span><span class="s">"custom_value"</span><span class="p" data-group-id="1619136303-2">)</span><span class="w">
</span><span class="ss">:ok</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">meta</span><span class="p" data-group-id="1619136303-3">(</span><span class="nc">Registry.PutMetaTest</span><span class="p">,</span><span class="w"> </span><span class="ss">:custom_key</span><span class="p" data-group-id="1619136303-3">)</span><span class="w">
</span><span class="p" data-group-id="1619136303-4">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="s">"custom_value"</span><span class="p" data-group-id="1619136303-4">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">put_meta</span><span class="p" data-group-id="1619136303-5">(</span><span class="nc">Registry.PutMetaTest</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="1619136303-6">{</span><span class="ss">:tuple</span><span class="p">,</span><span class="w"> </span><span class="ss">:key</span><span class="p" data-group-id="1619136303-6">}</span><span class="p">,</span><span class="w"> </span><span class="s">"tuple_value"</span><span class="p" data-group-id="1619136303-5">)</span><span class="w">
</span><span class="ss">:ok</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">meta</span><span class="p" data-group-id="1619136303-7">(</span><span class="nc">Registry.PutMetaTest</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="1619136303-8">{</span><span class="ss">:tuple</span><span class="p">,</span><span class="w"> </span><span class="ss">:key</span><span class="p" data-group-id="1619136303-8">}</span><span class="p" data-group-id="1619136303-7">)</span><span class="w">
</span><span class="p" data-group-id="1619136303-9">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="s">"tuple_value"</span><span class="p" data-group-id="1619136303-9">}</span></code></pre>
</section>
</div>
<div class="detail" id="register/3">
<div class="detail-header">
<a href="#register/3" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
<span class="sr-only">Link to this function</span>
</a>
<span class="signature">register(registry, key, value)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L874" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
<span class="sr-only">View Source</span>
</a>
<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>register(<a href="#t:registry/0">registry</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) ::
{:ok, <a href="typespecs.html#basic-types">pid</a>()} | {:error, {:already_registered, <a href="typespecs.html#basic-types">pid</a>()}}</pre>
</div>
</div>
<section class="docstring">
<p>Registers the current process under the given <code class="inline">key</code> in <code class="inline">registry</code>.</p>
<p>A value to be associated with this registration must also be given.
This value will be retrieved whenever dispatching or doing a key
lookup.</p>
<p>This function returns <code class="inline">{:ok, owner}</code> or <code class="inline">{:error, reason}</code>.
The <code class="inline">owner</code> is the pid in the registry partition responsible for
the pid. The owner is automatically linked to the caller.</p>
<p>If the registry has unique keys, it will return <code class="inline">{:ok, owner}</code> unless
the key is already associated to a pid, in which case it returns
<code class="inline">{:error, {:already_registered, pid}}</code>.</p>
<p>If the registry has duplicate keys, multiple registrations from the
current process under the same key are allowed.</p>
<h2 id="register/3-examples" class="section-heading">
<a href="#register/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>Registering under a unique registry does not allow multiple entries:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="9613992674-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.UniqueRegisterTest</span><span class="p" data-group-id="9613992674-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="9613992674-2">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="9613992674-2">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="9613992674-3">(</span><span class="nc">Registry.UniqueRegisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="9613992674-3">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="9613992674-4">(</span><span class="nc">Registry.UniqueRegisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:later</span><span class="p" data-group-id="9613992674-4">)</span><span class="w">
</span><span class="p" data-group-id="9613992674-5">{</span><span class="ss">:error</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9613992674-6">{</span><span class="ss">:already_registered</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="9613992674-7">(</span><span class="p" data-group-id="9613992674-7">)</span><span class="p" data-group-id="9613992674-6">}</span><span class="p" data-group-id="9613992674-5">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="9613992674-8">(</span><span class="nc">Registry.UniqueRegisterTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="9613992674-9">(</span><span class="p" data-group-id="9613992674-9">)</span><span class="p" data-group-id="9613992674-8">)</span><span class="w">
</span><span class="p" data-group-id="9613992674-10">[</span><span class="s">"hello"</span><span class="p" data-group-id="9613992674-10">]</span></code></pre>
<p>Such is possible for duplicate registries though:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="4535753236-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.DuplicateRegisterTest</span><span class="p" data-group-id="4535753236-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="4535753236-2">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="4535753236-2">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4535753236-3">(</span><span class="nc">Registry.DuplicateRegisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="4535753236-3">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="4535753236-4">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="4535753236-4">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4535753236-5">(</span><span class="nc">Registry.DuplicateRegisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="4535753236-5">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="4535753236-6">(</span><span class="nc">Registry.DuplicateRegisterTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4535753236-7">(</span><span class="p" data-group-id="4535753236-7">)</span><span class="p" data-group-id="4535753236-6">)</span><span class="w">
</span><span class="p" data-group-id="4535753236-8">[</span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="4535753236-8">]</span></code></pre>
</section>
</div>
<div class="detail" id="start_link/1">
<div class="detail-header">
<a href="#start_link/1" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
<span class="sr-only">Link to this function</span>
</a>
<span class="signature">start_link(options)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L284" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
<span class="sr-only">View Source</span>
</a>
<span class="note">(since 1.5.0)</span>
<div class="specs">
<pre>start_link(
keys: <a href="#t:keys/0">keys</a>(),
name: <a href="#t:registry/0">registry</a>(),
partitions: <a href="typespecs.html#basic-types">pos_integer</a>(),
listeners: [<a href="typespecs.html#basic-types">atom</a>()],
meta: meta
) :: {:ok, <a href="typespecs.html#basic-types">pid</a>()} | {:error, <a href="typespecs.html#built-in-types">term</a>()}
when meta: [{<a href="#t:meta_key/0">meta_key</a>(), <a href="#t:meta_value/0">meta_value</a>()}]</pre>
</div>
</div>
<section class="docstring">
<p>Starts the registry as a supervisor process.</p>
<p>Manually it can be started as:</p>
<pre><code class="nohighlight makeup elixir"><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="1852992760-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">MyApp.Registry</span><span class="p" data-group-id="1852992760-1">)</span></code></pre>
<p>In your supervisor tree, you would write:</p>
<pre><code class="nohighlight makeup elixir"><span class="nc">Supervisor</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="5526244157-1">(</span><span class="p" data-group-id="5526244157-2">[</span><span class="w">
</span><span class="p" data-group-id="5526244157-3">{</span><span class="nc">Registry</span><span class="p">,</span><span class="w"> </span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">MyApp.Registry</span><span class="p" data-group-id="5526244157-3">}</span><span class="w">
</span><span class="p" data-group-id="5526244157-2">]</span><span class="p" data-group-id="5526244157-1">)</span></code></pre>
<p>For intensive workloads, the registry may also be partitioned (by specifying
the <code class="inline">:partitions</code> option). If partitioning is required then a good default is to
set the number of partitions to the number of schedulers available:</p>
<pre><code class="nohighlight makeup elixir"><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="5576269255-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">MyApp.Registry</span><span class="p">,</span><span class="w">
</span><span class="ss">partitions</span><span class="p">:</span><span class="w"> </span><span class="nc">System</span><span class="o">.</span><span class="n">schedulers_online</span><span class="p" data-group-id="5576269255-2">(</span><span class="p" data-group-id="5576269255-2">)</span><span class="p" data-group-id="5576269255-1">)</span></code></pre>
<p>or:</p>
<pre><code class="nohighlight makeup elixir"><span class="nc">Supervisor</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="5594430134-1">(</span><span class="p" data-group-id="5594430134-2">[</span><span class="w">
</span><span class="p" data-group-id="5594430134-3">{</span><span class="nc">Registry</span><span class="p">,</span><span class="w"> </span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">MyApp.Registry</span><span class="p">,</span><span class="w">
</span><span class="ss">partitions</span><span class="p">:</span><span class="w"> </span><span class="nc">System</span><span class="o">.</span><span class="n">schedulers_online</span><span class="p" data-group-id="5594430134-4">(</span><span class="p" data-group-id="5594430134-4">)</span><span class="p" data-group-id="5594430134-3">}</span><span class="w">
</span><span class="p" data-group-id="5594430134-2">]</span><span class="p" data-group-id="5594430134-1">)</span></code></pre>
<h2 id="start_link/1-options" class="section-heading">
<a href="#start_link/1-options" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Options
</h2>
<p>The registry requires the following keys:</p>
<ul>
<li><code class="inline">:keys</code> - choose if keys are <code class="inline">:unique</code> or <code class="inline">:duplicate</code>
</li>
<li><code class="inline">:name</code> - the name of the registry and its tables
</li>
</ul>
<p>The following keys are optional:</p>
<ul>
<li><code class="inline">:partitions</code> - the number of partitions in the registry. Defaults to <code class="inline">1</code>.
</li>
<li><code class="inline">:listeners</code> - a list of named processes which are notified of <code class="inline">:register</code>
and <code class="inline">:unregister</code> events. The registered process must be monitored by the
listener if the listener wants to be notified if the registered process
crashes.
</li>
<li><code class="inline">:meta</code> - a keyword list of metadata to be attached to the registry.
</li>
</ul>
</section>
</div>
<div class="detail" id="unregister/2">
<div class="detail-header">
<a href="#unregister/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
<span class="sr-only">Link to this function</span>
</a>
<span class="signature">unregister(registry, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L720" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
<span class="sr-only">View Source</span>
</a>
<span class="note">(since 1.4.0)</span>
<div class="specs">
<pre>unregister(<a href="#t:registry/0">registry</a>(), <a href="#t:key/0">key</a>()) :: :ok</pre>
</div>
</div>
<section class="docstring">
<p>Unregisters all entries for the given <code class="inline">key</code> associated to the current
process in <code class="inline">registry</code>.</p>
<p>Always returns <code class="inline">:ok</code> and automatically unlinks the current process from
the owner if there are no more keys associated to the current process. See
also <a href="#register/3"><code class="inline">register/3</code></a> to read more about the “owner”.</p>
<h2 id="unregister/2-examples" class="section-heading">
<a href="#unregister/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>For unique registries:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="5192231845-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.UniqueUnregisterTest</span><span class="p" data-group-id="5192231845-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="5192231845-2">(</span><span class="nc">Registry.UniqueUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="5192231845-2">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="5192231845-3">(</span><span class="nc">Registry.UniqueUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="5192231845-4">(</span><span class="p" data-group-id="5192231845-4">)</span><span class="p" data-group-id="5192231845-3">)</span><span class="w">
</span><span class="p" data-group-id="5192231845-5">[</span><span class="s">"hello"</span><span class="p" data-group-id="5192231845-5">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">unregister</span><span class="p" data-group-id="5192231845-6">(</span><span class="nc">Registry.UniqueUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="5192231845-6">)</span><span class="w">
</span><span class="ss">:ok</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="5192231845-7">(</span><span class="nc">Registry.UniqueUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="5192231845-8">(</span><span class="p" data-group-id="5192231845-8">)</span><span class="p" data-group-id="5192231845-7">)</span><span class="w">
</span><span class="p" data-group-id="5192231845-9">[</span><span class="p" data-group-id="5192231845-9">]</span></code></pre>
<p>For duplicate registries:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="4081893928-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.DuplicateUnregisterTest</span><span class="p" data-group-id="4081893928-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4081893928-2">(</span><span class="nc">Registry.DuplicateUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="4081893928-2">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="4081893928-3">(</span><span class="nc">Registry.DuplicateUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="4081893928-3">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="4081893928-4">(</span><span class="nc">Registry.DuplicateUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4081893928-5">(</span><span class="p" data-group-id="4081893928-5">)</span><span class="p" data-group-id="4081893928-4">)</span><span class="w">
</span><span class="p" data-group-id="4081893928-6">[</span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="4081893928-6">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">unregister</span><span class="p" data-group-id="4081893928-7">(</span><span class="nc">Registry.DuplicateUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="4081893928-7">)</span><span class="w">
</span><span class="ss">:ok</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="4081893928-8">(</span><span class="nc">Registry.DuplicateUnregisterTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="4081893928-9">(</span><span class="p" data-group-id="4081893928-9">)</span><span class="p" data-group-id="4081893928-8">)</span><span class="w">
</span><span class="p" data-group-id="4081893928-10">[</span><span class="p" data-group-id="4081893928-10">]</span></code></pre>
</section>
</div>
<div class="detail" id="unregister_match/4">
<span id="unregister_match/3"></span>
<div class="detail-header">
<a href="#unregister_match/4" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
<span class="sr-only">Link to this function</span>
</a>
<span class="signature">unregister_match(registry, key, pattern, guards \\ [])</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L780" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
<span class="sr-only">View Source</span>
</a>
<span class="note">(since 1.5.0)</span>
</div>
<section class="docstring">
<p>Unregister entries for a given key matching a pattern.</p>
<h2 id="unregister_match/4-examples" class="section-heading">
<a href="#unregister_match/4-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<p>For unique registries it can be used to conditionally unregister a key on
the basis of whether or not it matches a particular value.</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="5096865081-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.UniqueUnregisterMatchTest</span><span class="p" data-group-id="5096865081-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="5096865081-2">(</span><span class="nc">Registry.UniqueUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="5096865081-2">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="5096865081-3">(</span><span class="nc">Registry.UniqueUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="5096865081-4">(</span><span class="p" data-group-id="5096865081-4">)</span><span class="p" data-group-id="5096865081-3">)</span><span class="w">
</span><span class="p" data-group-id="5096865081-5">[</span><span class="s">"hello"</span><span class="p" data-group-id="5096865081-5">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">unregister_match</span><span class="p" data-group-id="5096865081-6">(</span><span class="nc">Registry.UniqueUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:foo</span><span class="p" data-group-id="5096865081-6">)</span><span class="w">
</span><span class="ss">:ok</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="5096865081-7">(</span><span class="nc">Registry.UniqueUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="5096865081-8">(</span><span class="p" data-group-id="5096865081-8">)</span><span class="p" data-group-id="5096865081-7">)</span><span class="w">
</span><span class="p" data-group-id="5096865081-9">[</span><span class="s">"hello"</span><span class="p" data-group-id="5096865081-9">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">unregister_match</span><span class="p" data-group-id="5096865081-10">(</span><span class="nc">Registry.UniqueUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world</span><span class="p" data-group-id="5096865081-10">)</span><span class="w">
</span><span class="ss">:ok</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="5096865081-11">(</span><span class="nc">Registry.UniqueUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="5096865081-12">(</span><span class="p" data-group-id="5096865081-12">)</span><span class="p" data-group-id="5096865081-11">)</span><span class="w">
</span><span class="p" data-group-id="5096865081-13">[</span><span class="p" data-group-id="5096865081-13">]</span></code></pre>
<p>For duplicate registries:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="2046026702-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:duplicate</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p" data-group-id="2046026702-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="2046026702-2">(</span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world_a</span><span class="p" data-group-id="2046026702-2">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="2046026702-3">(</span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world_b</span><span class="p" data-group-id="2046026702-3">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="2046026702-4">(</span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world_c</span><span class="p" data-group-id="2046026702-4">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="2046026702-5">(</span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="2046026702-6">(</span><span class="p" data-group-id="2046026702-6">)</span><span class="p" data-group-id="2046026702-5">)</span><span class="w">
</span><span class="p" data-group-id="2046026702-7">[</span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="2046026702-7">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">unregister_match</span><span class="p" data-group-id="2046026702-8">(</span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="ss">:world_a</span><span class="p" data-group-id="2046026702-8">)</span><span class="w">
</span><span class="ss">:ok</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="2046026702-9">(</span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="n">self</span><span class="p" data-group-id="2046026702-10">(</span><span class="p" data-group-id="2046026702-10">)</span><span class="p" data-group-id="2046026702-9">)</span><span class="w">
</span><span class="p" data-group-id="2046026702-11">[</span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="2046026702-11">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="2046026702-12">(</span><span class="nc">Registry.DuplicateUnregisterMatchTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="2046026702-12">)</span><span class="w">
</span><span class="p" data-group-id="2046026702-13">[</span><span class="p" data-group-id="2046026702-14">{</span><span class="n">self</span><span class="p" data-group-id="2046026702-15">(</span><span class="p" data-group-id="2046026702-15">)</span><span class="p">,</span><span class="w"> </span><span class="ss">:world_b</span><span class="p" data-group-id="2046026702-14">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="2046026702-16">{</span><span class="n">self</span><span class="p" data-group-id="2046026702-17">(</span><span class="p" data-group-id="2046026702-17">)</span><span class="p">,</span><span class="w"> </span><span class="ss">:world_c</span><span class="p" data-group-id="2046026702-16">}</span><span class="p" data-group-id="2046026702-13">]</span></code></pre>
</section>
</div>
<div class="detail" id="update_value/3">
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<span class="signature">update_value(registry, key, callback)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/registry.ex#L370" class="view-source" rel="help" title="View Source">
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<span class="note">(since 1.4.0)</span>
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<pre>update_value(<a href="#t:registry/0">registry</a>(), <a href="#t:key/0">key</a>(), (<a href="#t:value/0">value</a>() -> <a href="#t:value/0">value</a>())) ::
{new_value :: <a href="typespecs.html#built-in-types">term</a>(), old_value :: <a href="typespecs.html#built-in-types">term</a>()} | :error</pre>
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<section class="docstring">
<p>Updates the value for <code class="inline">key</code> for the current process in the unique <code class="inline">registry</code>.</p>
<p>Returns a <code class="inline">{new_value, old_value}</code> tuple or <code class="inline">:error</code> if there
is no such key assigned to the current process.</p>
<p>If a non-unique registry is given, an error is raised.</p>
<h2 id="update_value/3-examples" class="section-heading">
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Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">start_link</span><span class="p" data-group-id="0284054556-1">(</span><span class="ss">keys</span><span class="p">:</span><span class="w"> </span><span class="ss">:unique</span><span class="p">,</span><span class="w"> </span><span class="ss">name</span><span class="p">:</span><span class="w"> </span><span class="nc">Registry.UpdateTest</span><span class="p" data-group-id="0284054556-1">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="p" data-group-id="0284054556-2">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="bp">_</span><span class="p" data-group-id="0284054556-2">}</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">register</span><span class="p" data-group-id="0284054556-3">(</span><span class="nc">Registry.UpdateTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0284054556-3">)</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="0284054556-4">(</span><span class="nc">Registry.UpdateTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="0284054556-4">)</span><span class="w">
</span><span class="p" data-group-id="0284054556-5">[</span><span class="p" data-group-id="0284054556-6">{</span><span class="n">self</span><span class="p" data-group-id="0284054556-7">(</span><span class="p" data-group-id="0284054556-7">)</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0284054556-6">}</span><span class="p" data-group-id="0284054556-5">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">update_value</span><span class="p" data-group-id="0284054556-8">(</span><span class="nc">Registry.UpdateTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="p" data-group-id="0284054556-9">(</span><span class="ni">&1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0284054556-9">)</span><span class="p" data-group-id="0284054556-8">)</span><span class="w">
</span><span class="p" data-group-id="0284054556-10">{</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0284054556-10">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Registry</span><span class="o">.</span><span class="n">lookup</span><span class="p" data-group-id="0284054556-11">(</span><span class="nc">Registry.UpdateTest</span><span class="p">,</span><span class="w"> </span><span class="s">"hello"</span><span class="p" data-group-id="0284054556-11">)</span><span class="w">
</span><span class="p" data-group-id="0284054556-12">[</span><span class="p" data-group-id="0284054556-13">{</span><span class="n">self</span><span class="p" data-group-id="0284054556-14">(</span><span class="p" data-group-id="0284054556-14">)</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0284054556-13">}</span><span class="p" data-group-id="0284054556-12">]</span></code></pre>
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