diff --git a/resources/grammar/c3.l b/resources/grammar/c3.l
index 4add6a072..6e24cb5de 100644
--- a/resources/grammar/c3.l
+++ b/resources/grammar/c3.l
@@ -18,7 +18,7 @@ E			[Ee][+-]?{D}+
 P           [Pp][+-]?{D}+
 B64         [ \t\v\n\f]?[A-Za-z0-9+/][ \t\v\n\fA-Za-z0-9+/=]+
 HEX         [ \t\v\n\f]?[A-Fa-f0-9][ \t\v\n\fA-Fa-f0-9]+
-INTTYPE     [ui](8|16|32|64|128)?
+INTTYPE     (([ui](8|16|32|64|128))|([Uu][Ll]?|[Ll]))?
 REALTYPE    [f](8|16|32|64|128)?
 INT         {D}(_*{D})*
 HINT        {H}(_*{H})*