diff --git a/CHANGES b/CHANGES
index cba813f..07eddd4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -72,7 +72,7 @@ The following are the changes from calc version 2.14.3.5 to date:
     appear to meet calc requirements, or undefines CHK_C
     when it does not.
 
-    Added int.h as a centeral place for calc integer types and
+    Added int.h as a central place for calc integer types and
     integer macros.
 
 
diff --git a/int.h b/int.h
index 314350a..d610cab 100644
--- a/int.h
+++ b/int.h
@@ -1,6 +1,11 @@
 /*
  * int - integer types and integer macros used in calc
  *
+ * For general information on C integers, see:
+ *
+ *	https://en.cppreference.com/w/c/language/arithmetic_types
+ *	https://en.cppreference.com/w/c/types/integer
+ *
  * Copyright (C) 2023  Landon Curt Noll
  *
  * Primary author:  Landon Curt Noll
@@ -119,7 +124,6 @@
 #endif /* UINTMAX_WIDTH */
 
 
-
 /*
  * case: C compiler and/or select include files do not meet calc requirements
  */
@@ -130,7 +134,7 @@
  * calc v2 is the last version where one might be able to use an old C compiler
  *	   and/or tolerate missing include files
  */
-#if defined(CALC2_COMPAT)
+#if MAJOR_VER < 3
 
 
 /*
@@ -195,18 +199,16 @@
 #endif /* UINTMAX_WIDTH */
 
 
-
-#else /* CALC2_COMPAT */
+#else /* MAJOR_VER < 3 */
 
 
 /*
- * CHK_C undefuned and not calc v2 is an error
+ * calc v3 or later and CHK_C is undefined
  */
-#pragma GCC error "CHK_C undefined: C compiler and/or select include files do not meet calc requirements"
-#pragma GCC error "CALC2_COMPAT undefined: calc v3 and later requires CHK_C"
+#pragma GCC error "calc v3 and later require C compiler and include files that support CHK_C"
 
 
-#endif /* CALC2_COMPAT */
+#endif /* MAJOR_VER < 3 */
 #endif /* CHK_C */