diff --git a/reference/sem/functions/shm-put-var.xml b/reference/sem/functions/shm-put-var.xml
index ad01946f0e..a93e0ff95a 100644
--- a/reference/sem/functions/shm-put-var.xml
+++ b/reference/sem/functions/shm-put-var.xml
@@ -52,8 +52,10 @@
      <term><parameter>variable</parameter></term>
      <listitem>
       <para>
-       The variable. All <link linkend="language.types">variable-types</link>
-       except resources are supported.
+       The variable. All <link linkend="language.types">variable types</link>
+       that <function>serialize</function> supports may be used: generally
+       this means all types except for resources and some internal objects
+       that cannot be serialized.
       </para>
      </listitem>
     </varlistentry>