diff --git a/include/ucore/mbuf.h b/include/ucore/mbuf.h
index 27cc959..f6a1767 100644
--- a/include/ucore/mbuf.h
+++ b/include/ucore/mbuf.h
@@ -4,17 +4,6 @@
 #include <stddef.h>
 #include "tailq.h"
 
-#ifndef UC_INLINE
-#ifdef __GNUC__
-#  ifdef __clang__
-#    define UC_INLINE inline __attribute__((always_inline))
-#  else
-#    define UC_INLINE inline __attribute__((always_inline,flatten))
-#  endif
-#else
-#  define UC_INLINE inline
-#endif
-#endif
 
 /** @file
  * mbuf - A managed message/memory buffer.
@@ -220,6 +209,4 @@ static UC_INLINE uint8_t *uc_mbuf_head(struct MBuf* mbuf)
     return mbuf->head;
 }
 
-#undef UC_INLINE
-
 #endif
diff --git a/include/ucore/pack.h b/include/ucore/pack.h
index 6553b7e..889adcc 100644
--- a/include/ucore/pack.h
+++ b/include/ucore/pack.h
@@ -2,18 +2,7 @@
 #define UC_PACK_H_
 
 #include <stdint.h>
-
-#ifndef UC_INLINE
-#ifdef __GNUC__
-#  ifdef __clang__
-#    define UC_INLINE inline __attribute__((always_inline))
-#  else
-#    define UC_INLINE inline __attribute__((always_inline,flatten))
-#  endif
-#else
-#  define UC_INLINE inline
-#endif
-#endif
+#include "utils.h"
 
 /** @file
  * Functions for serializing/de-serializing integers to and from
diff --git a/include/ucore/tailq.h b/include/ucore/tailq.h
index a4ebd6f..ae6da60 100644
--- a/include/ucore/tailq.h
+++ b/include/ucore/tailq.h
@@ -1,17 +1,8 @@
 #ifndef UC_TAILQ_H_
 #define UC_TAILQ_H_
 
-#ifndef UC_INLINE
-#ifdef __GNUC__
-#  ifdef __clang__
-#    define UC_INLINE inline __attribute__((always_inline))
-#  else
-#    define UC_INLINE inline __attribute__((always_inline,flatten))
-#  endif
-#else
-#  define UC_INLINE inline
-#endif
-#endif
+#include "utils.h"
+
 /**
  * Doubly Linked List.
  * It is used either as
@@ -253,6 +244,4 @@ static UC_INLINE void uc_tailq_move_tail(struct TailQ *entry, struct TailQ *head
         (ptr) = (prv),\
         (prv) = UC_TAILQ_CONTAINER(UC_TAILQ_NEXT(&(ptr)->member), typeof(*ptr), member)) 
 
-#undef UC_INLINE
-
 #endif
diff --git a/include/ucore/utils.h b/include/ucore/utils.h
index 44511ff..9811e1b 100644
--- a/include/ucore/utils.h
+++ b/include/ucore/utils.h
@@ -120,5 +120,16 @@ const typeof( ((const type *)0)->member ) *__mptr = (ptr);    \
  */
 #define UC_UNUSED(x) x __attribute__((unused))
 
+
+#ifdef __GNUC__
+#  ifdef __clang__
+#    define UC_INLINE inline __attribute__((always_inline))
+#  else
+#    define UC_INLINE inline __attribute__((always_inline,flatten))
+#  endif
+#else
+#  define UC_INLINE inline
+#endif
+
 #endif