diff --git a/reference/sem/functions/sem-get.xml b/reference/sem/functions/sem-get.xml
index 01d99641a2a0..861251adc9c7 100644
--- a/reference/sem/functions/sem-get.xml
+++ b/reference/sem/functions/sem-get.xml
@@ -120,6 +120,15 @@
     otherwise PHP will be unable to access the semaphore.
    </simpara>
   </warning>
+  <warning>
+   <simpara>
+    If <parameter>auto_release</parameter> is enabled, the acquisitions held by a
+    <classname>SysvSemaphore</classname> object are also released as soon as the
+    object is freed, for example when the variable holding it is unset,
+    overwritten or goes out of scope, not only on request shutdown. Keep a
+    reference to the object for as long as the semaphore needs to stay acquired.
+   </simpara>
+  </warning>
  </refsect1>
 
  <refsect1 role="seealso">