+#define __compiletime_assert(condition, msg, prefix, suffix) \
+ do { \
+ bool __cond = !(condition); \
+ extern void prefix ## suffix(void) __compiletime_error(msg); \
+ if (__cond) \
+ prefix ## suffix(); \
+ __compiletime_error_fallback(__cond); \
+ } while (0)
+
+#define _compiletime_assert(condition, msg, prefix, suffix) \
+ __compiletime_assert(condition, msg, prefix, suffix)
+
+/**
+ * compiletime_assert - break build and emit msg if condition is false
+ * @condition: a compile-time constant condition to check
+ * @msg: a message to emit if condition is false
+ *
+ * In tradition of POSIX assert, this macro will break the build if the
+ * supplied condition is *false*, emitting the supplied error message if the
+ * compiler has support to do so.
+ */
+#define compiletime_assert(condition, msg) \
+ _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
+
+#define compiletime_assert_atomic_type(t) \
+ compiletime_assert(__native_word(t), \
+ "Need native word sized stores/loads for atomicity.")
+