diff --git a/xxhash.h b/xxhash.h
index 124204f0..311a69c7 100644
--- a/xxhash.h
+++ b/xxhash.h
@@ -733,14 +733,12 @@ XXH_PUBLIC_API XXH_PUREF XXH32_hash_t XXH32_hashFromCanonical(const XXH32_canoni
  * CPP17 : https://en.cppreference.com/w/cpp/language/attributes/fallthrough
  * C23   : https://en.cppreference.com/w/c/language/attributes/fallthrough
  */
-#if XXH_HAS_C_ATTRIBUTE(x)
-# define XXH_FALLTHROUGH [[fallthrough]]
-#elif XXH_HAS_CPP_ATTRIBUTE(x)
+#if XXH_HAS_C_ATTRIBUTE(fallthrough) || XXH_HAS_CPP_ATTRIBUTE(fallthrough)
 # define XXH_FALLTHROUGH [[fallthrough]]
 #elif XXH_HAS_ATTRIBUTE(__fallthrough__)
-# define XXH_FALLTHROUGH __attribute__ ((fallthrough))
+# define XXH_FALLTHROUGH __attribute__ ((__fallthrough__))
 #else
-# define XXH_FALLTHROUGH
+# define XXH_FALLTHROUGH /* fallthrough */
 #endif
 
 /*!