diff --git a/include/Mw/BaseTypes.h b/include/Mw/BaseTypes.h
index a6df20c..9a0ef28 100644
--- a/include/Mw/BaseTypes.h
+++ b/include/Mw/BaseTypes.h
@@ -17,17 +17,19 @@ typedef unsigned char MwBool;
 #define MwFALSE ((MwBool)0)
 
 #if __STDC_VERSION__ >= 199901L || __GNUC__ > 2
-typedef long long MwOffset;
-typedef unsigned long long MwUOffset;
+typedef long long MwI64;
+typedef unsigned long long MwU64;
 #elif defined(_MSC_VER) || defined(__BORLANDC__) || defined(__WATCOMC__)
-typedef __int64 MwOffset;
-typedef unsigned __int64 MwUOffset;
+typedef __int64 MwI64;
+typedef unsigned __int64 MwU64;
 #else
 /* out of hope */
-typedef long MwOffset;
-typedef unsigned long MwUOffset;
+typedef long MwI64;
+typedef unsigned long MwU64;
 #endif
 
+typedef MwI64 MwOffset;
+
 struct _MwPoint {
 	int x;
 	int y;