--- a/stage1_2/iec_flex.ll	Wed May 11 19:38:31 2016 +0100
+++ b/stage1_2/iec_flex.ll	Fri May 13 12:18:50 2016 +0100
@@ -1367,6 +1367,10 @@
 DATE_AND_TIME	return DATE_AND_TIME;	/* Keyword (Data Type) */
 TIME_OF_DAY	return TIME_OF_DAY;	/* Keyword (Data Type) */
 
+					/* A non-standard extension! */
+VOID		{if (runtime_options.allow_void_datatype) {return VOID;}          else {REJECT;}} 
+
+
 	/*****************************************************************/
 	/* Keywords defined in "Safety Software Technical Specification" */
 	/*****************************************************************/