diff --git a/reference/sockets/constants.xml b/reference/sockets/constants.xml
index 1cf59a8e07..1e7f555cd3 100644
--- a/reference/sockets/constants.xml
+++ b/reference/sockets/constants.xml
@@ -180,6 +180,19 @@
     </simpara>
    </listitem>
   </varlistentry>
+  <varlistentry xml:id="constant.so-reuseport">
+   <term>
+    <constant>SO_REUSEPORT</constant> 
+    (<type>integer</type>)
+   </term>
+   <listitem>
+    <simpara>
+     This constant is only available in PHP 5.4.10 or later on platforms that
+     support the <constant>SO_REUSEPORT</constant> socket option: this
+     includes Mac OS X and FreeBSD, but does not include Linux or Windows.
+    </simpara>
+   </listitem>
+  </varlistentry>
   <varlistentry xml:id="constant.so-keepalive">
    <term>
     <constant>SO_KEEPALIVE</constant>