--- a/lib/accessor.h	Wed Mar 19 12:13:43 2014 +0000
+++ b/lib/accessor.h	Thu Mar 20 10:29:39 2014 +0100
@@ -116,9 +116,9 @@
 #define __SET_VAR(prefix, name, new_value, ...)\
 	if (!(prefix name.flags & __IEC_FORCE_FLAG)) prefix name.value __VA_ARGS__ = new_value
 #define __SET_EXTERNAL(prefix, name, new_value, ...)\
-	{extern IEC_BYTE __IS_GLOBAL_##name##_FORCED();\
-    if (!(prefix name.flags & __IEC_FORCE_FLAG || __IS_GLOBAL_##name##_FORCED()))\
-		(*(prefix name.value)) __VA_ARGS__ = new_value;}
+	{extern IEC_BYTE __IS_GLOBAL_##name##_FORCED(void);\
+     if (!(prefix name.flags & __IEC_FORCE_FLAG || __IS_GLOBAL_##name##_FORCED()))\
+		 (*(prefix name.value)) __VA_ARGS__ = new_value;}
 #define __SET_EXTERNAL_FB(prefix, name, new_value, ...)\
 	__SET_VAR((*(prefix name)), __VA_ARGS__, new_value)
 #define __SET_LOCATED(prefix, name, new_value, ...)\