+#ifdef __cplusplus
+#define caa_unqual_scalar_typeof(x) \
+ std::remove_cv<std::remove_reference<decltype(x)>::type>::type
+#else
+#define caa_scalar_type_to_expr(type) \
+ unsigned type: (unsigned type)0, \
+ signed type: (signed type)0
+
+/*
+ * Use C11 _Generic to express unqualified type from expression. This removes
+ * volatile qualifier from expression type.
+ */
+#define caa_unqual_scalar_typeof(x) \
+ __typeof__( \
+ _Generic((x), \
+ char: (char)0, \
+ caa_scalar_type_to_expr(char), \
+ caa_scalar_type_to_expr(short), \
+ caa_scalar_type_to_expr(int), \
+ caa_scalar_type_to_expr(long), \
+ caa_scalar_type_to_expr(long long), \
+ default: (x) \
+ ) \
+ )
+#endif
+
+/*
+ * Allow user to manually define CMM_SANITIZE_THREAD if their toolchain is not
+ * supported by this check.
+ */
+#ifndef CMM_SANITIZE_THREAD
+# if defined(__GNUC__) && defined(__SANITIZE_THREAD__)
+# define CMM_SANITIZE_THREAD
+# elif defined(__clang__) && defined(__has_feature)
+# if __has_feature(thread_sanitizer)
+# define CMM_SANITIZE_THREAD
+# endif
+# endif
+#endif /* !CMM_SANITIZE_THREAD */
+
+/*
+ * Helper to add the volatile qualifier to a pointer.
+ */
+#if defined __cplusplus
+template <typename T>
+volatile T cmm_cast_volatile(T t)
+{
+ return static_cast<volatile T>(t);
+}
+#else
+# define cmm_cast_volatile(ptr) \
+ __extension__ \
+ ({ \
+ (volatile __typeof__(ptr))(ptr); \
+ })
+#endif
+