diff --git a/src/ca/os_depen.h b/src/ca/os_depen.h
index f8b7fd796..bb582423e 100644
--- a/src/ca/os_depen.h
+++ b/src/ca/os_depen.h
@@ -13,6 +13,7 @@
  *			Also droped the TCPDELAY to 50 mS
  *	.03 joh	090391	Updated for V5 vxWorks
  *	.04 joh 092491	changed order of ops on LOCALTICKS
+ *	.05 joh	092691	added NELEMENTS()
  *
  */
 
@@ -56,6 +57,10 @@
 #define ERROR            (-1)
 #endif  
 
+#ifndef NELEMENTS
+#define NELEMENTS(array)    (sizeof(array)/sizeof((array)[0]))
+#endif
+
 /************************************************************************/
 /*	Provided to enforce one thread at a time code sections		*/
 /*	independent of a particular operating system			*/
@@ -133,7 +138,7 @@
 		void 		*device;
 	};
 	static char	ca_unique_address;
-	#define		MYTIMERID  (&ca_unique_address)
+#	define		MYTIMERID  (&ca_unique_address)
 #endif