diff --git a/reference/pgsql/functions/pg-escape-literal.xml b/reference/pgsql/functions/pg-escape-literal.xml
index 891aad837e..f0b34997e3 100644
--- a/reference/pgsql/functions/pg-escape-literal.xml
+++ b/reference/pgsql/functions/pg-escape-literal.xml
@@ -47,6 +47,8 @@
        <parameter>connection</parameter> is not present, the default connection 
        is used. The default connection is the last connection made by 
        <function>pg_connect</function> or <function>pg_pconnect</function>.
+       When there is no default connection, it raises <literal>E_WARNING</literal>
+       and returns &false;.
       </para>
      </listitem>
     </varlistentry>