# define INT64_C(c) CAT2(c,L)
# define UINT64_C(c) CAT2(c,UL)
# else
-# define INT64_C(c) ((I64TYPE)(c))
-# define UINT64_C(c) ((U64TYPE)(c))
+# if defined(_WIN64) && defined(_MSC_VER)
+# define INT64_C(c) CAT2(c,I64)
+# define UINT64_C(c) CAT2(c,UI64)
+# else
+# define INT64_C(c) ((I64TYPE)(c))
+# define UINT64_C(c) ((U64TYPE)(c))
+# endif
# endif
# endif
# endif