diff --git a/include/__mutex_base b/include/__mutex_base
index 008be95..0c34a3b 100644
--- a/include/__mutex_base
+++ b/include/__mutex_base
@@ -51,7 +51,7 @@
 #else
     mutex() _NOEXCEPT {__m_ = (__libcpp_mutex_t)_LIBCPP_MUTEX_INITIALIZER;}
 #endif
-    ~mutex();
+    ~mutex() _NOEXCEPT;
 
 private:
     mutex(const mutex&);// = delete;