diff --git a/include/rtdef.h b/include/rtdef.h
index 7a983efb652c6c8df5333c71d6ae76e9591d261c..f7b87cc53efb3ae15df5a266019125c11bba0e01 100644
--- a/include/rtdef.h
+++ b/include/rtdef.h
@@ -83,6 +83,7 @@ typedef rt_base_t                       rt_off_t;       /**< Type for offset */
     #include <stdarg.h>
     #define SECTION(x)                  __attribute__((section(x)))
     #define UNUSED                      __attribute__((unused))
+	#define USED						__attribute__((used))
     #define ALIGN(n)                    __attribute__((aligned(n)))
     #define rt_inline                   static __inline
     /* module compiling */
@@ -128,6 +129,7 @@ typedef rt_base_t                       rt_off_t;       /**< Type for offset */
 
     #define SECTION(x)                  __attribute__((section(x)))
     #define UNUSED                      __attribute__((unused))
+	#define USED						__attribute__((used))
     #define ALIGN(n)                    __attribute__((aligned(n)))
     #define rt_inline                   static __inline
     #define RTT_API
@@ -147,6 +149,23 @@ typedef rt_base_t                       rt_off_t;       /**< Type for offset */
     #define RTT_API
 #endif
 
+/* initialization export */
+#ifdef RT_USING_COMPONENTS_INIT
+typedef int (*init_fn_t)(void);
+#define INIT_EXPORT(fn, level)	\
+	const init_fn_t __rt_init_##fn SECTION(".rti_fn."level) = fn
+#else
+#define INIT_EXPORT(fn, level)      
+#endif
+
+/* board init routines will be called in board_init() function */
+#define INIT_BOARD_EXPORT(fn)		INIT_EXPORT(fn, "1")
+/* device/component/fs/app init routines will be called in init_thread */
+#define INIT_DEVICE_EXPORT(fn)		INIT_EXPORT(fn, "2")
+#define INIT_COMPONENT_EXPORT(fn)	INIT_EXPORT(fn, "3")
+#define INIT_FS_EXPORT(fn)			INIT_EXPORT(fn, "4")
+#define INIT_APP_EXPORT(fn)			INIT_EXPORT(fn, "5")
+
 /* event length */
 #define RT_EVENT_LENGTH                 32