diff --git a/FixedWidthIntLiterals.h b/FixedWidthIntLiterals.h
index e197e4c..2b2923a 100644
--- a/FixedWidthIntLiterals.h
+++ b/FixedWidthIntLiterals.h
@@ -53,6 +53,8 @@
 #include <cstdint>
 #include <limits>
 
+#include <type_traits>
+
 #ifndef SCW_FIXEDWIDTH_INT_LITERALS_NAMESPACE
 #define SCW_FIXEDWIDTH_INT_LITERALS_NAMESPACE scw
 #endif
@@ -161,7 +163,7 @@ SCW_FIXEDWIDTH_DEFINE_CHECK_VALID_FUNC(size_t, "size_t literal out of range.");
 /// Finally the user-defined literal operators. Again with the macros?
 #define SCW_FIXEDWIDTH_DEFINE_INTEGER_OPERATOR(typesuffix_, typename_)                \
   template <char... digits>                                                \
-  constexpr typename_ operator"" typesuffix_() {                        \
+  constexpr typename_ operator""##typesuffix_() {                        \
     return detail::checkValid_##typename_<detail::createValue<digits...>()>(); \
   }