diff --git a/components/libc/compilers/common/readme.md b/components/libc/compilers/common/readme.md
index cb91d95f459082ba875224e4c1d0bc63c4f938dd..0cd56272ff2b65a03add637103afb72420cbe848 100644
--- a/components/libc/compilers/common/readme.md
+++ b/components/libc/compilers/common/readme.md
@@ -1 +1,10 @@
-This folder is "common" for armlibc newlibc and dlib. It's not "common" for minilibc.
\ No newline at end of file
+# Attention : 
+
+1. This folder is "common" for armlibc newlibc and dlib. It's not "common" for minilibc.
+
+2. If you want to add new .c files, please do not forget to fix SConscript file too. eg:
+
+```python
+if GetDepend('RT_USING_POSIX') == False:
+        SrcRemove(src, ['unistd.c'])
+```
\ No newline at end of file
diff --git a/components/net/lwip-1.4.1/src/arch/include/arch/cc.h b/components/net/lwip-1.4.1/src/arch/include/arch/cc.h
index 604477dab81bf7cc52b5763d54e5a81fd964dd44..80e90074595b861b66c3cfa20e14617f074d7faf 100644
--- a/components/net/lwip-1.4.1/src/arch/include/arch/cc.h
+++ b/components/net/lwip-1.4.1/src/arch/include/arch/cc.h
@@ -66,7 +66,7 @@ typedef uintptr_t mem_ptr_t;
 #endif /* __CC_ARM/__IAR_SYSTEMS_ICC__ */
 #endif
 
-#if defined(RT_USING_LIBC) || defined(RT_USING_MINILIBC) || defined(RT_LIBC_USING_TIME) || defined ( __GNUC__)
+#if defined(RT_USING_LIBC) || defined(RT_USING_MINILIBC) || defined(RT_LIBC_USING_TIME) || (defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 #include <sys/time.h>
 #define LWIP_TIMEVAL_PRIVATE	   0
 #else
@@ -78,10 +78,15 @@ typedef uintptr_t mem_ptr_t;
 #define PACK_STRUCT_STRUCT __attribute__ ((__packed__))
 #define PACK_STRUCT_BEGIN
 #define PACK_STRUCT_END
-#elif defined(__IAR_SYSTEMS_ICC__)   /* IAR Compiler */
+#elif defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050) /*Arm Compiler 6*/
+#define PACK_STRUCT_FIELD(x) x
+#define PACK_STRUCT_STRUCT __attribute__((packed))
 #define PACK_STRUCT_BEGIN
-#define PACK_STRUCT_STRUCT
 #define PACK_STRUCT_END
+#elif defined(__IAR_SYSTEMS_ICC__)   /* IAR Compiler */
+#define PACK_STRUCT_BEGIN   #pragma pack(1)
+#define PACK_STRUCT_STRUCT 
+#define PACK_STRUCT_END     #pragma pack()
 #define PACK_STRUCT_FIELD(x) x
 #define PACK_STRUCT_USE_INCLUDES
 #elif defined(__GNUC__)     /* GNU GCC Compiler */
diff --git a/components/net/lwip-2.0.2/src/arch/include/arch/cc.h b/components/net/lwip-2.0.2/src/arch/include/arch/cc.h
index 00536a84197a2525f13387fcef67e2a056333c00..8888995bcc860cb35b8c0eead646efa2b4706a6e 100644
--- a/components/net/lwip-2.0.2/src/arch/include/arch/cc.h
+++ b/components/net/lwip-2.0.2/src/arch/include/arch/cc.h
@@ -45,7 +45,7 @@
 #define S32_F "ld"
 #define X32_F "lx"
 
-#if defined(RT_USING_LIBC) || defined(RT_USING_MINILIBC) || defined(RT_LIBC_USING_TIME) || defined ( __GNUC__)
+#if defined(RT_USING_LIBC) || defined(RT_USING_MINILIBC) || defined(RT_LIBC_USING_TIME) || (defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 #include <sys/time.h>
 #define LWIP_TIMEVAL_PRIVATE	   0
 #else
@@ -57,10 +57,15 @@
 #define PACK_STRUCT_STRUCT __attribute__ ((__packed__))
 #define PACK_STRUCT_BEGIN
 #define PACK_STRUCT_END
-#elif defined(__IAR_SYSTEMS_ICC__)   /* IAR Compiler */
+#elif defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050) /*Arm Compiler 6*/
+#define PACK_STRUCT_FIELD(x) x
+#define PACK_STRUCT_STRUCT __attribute__((packed))
 #define PACK_STRUCT_BEGIN
-#define PACK_STRUCT_STRUCT
 #define PACK_STRUCT_END
+#elif defined(__IAR_SYSTEMS_ICC__)   /* IAR Compiler */
+#define PACK_STRUCT_BEGIN   #pragma pack(1)
+#define PACK_STRUCT_STRUCT
+#define PACK_STRUCT_END     #pragma pack()
 #define PACK_STRUCT_FIELD(x) x
 #define PACK_STRUCT_USE_INCLUDES
 #elif defined(__GNUC__)     /* GNU GCC Compiler */
diff --git a/components/net/lwip-2.1.2/src/arch/include/arch/cc.h b/components/net/lwip-2.1.2/src/arch/include/arch/cc.h
index 6905ecd442b0feedf8f3a277a1856c5a6763cfd6..61086b96d3aca7c0713fa3e587a5fe70ccfabd5d 100644
--- a/components/net/lwip-2.1.2/src/arch/include/arch/cc.h
+++ b/components/net/lwip-2.1.2/src/arch/include/arch/cc.h
@@ -59,7 +59,7 @@
 #endif /* __CC_ARM/__IAR_SYSTEMS_ICC__ */
 #endif /* RT_USING_LIBC */
 
-#if defined(RT_USING_LIBC) || defined(RT_USING_MINILIBC) || defined(RT_LIBC_USING_TIME) || defined ( __GNUC__)
+#if defined(RT_USING_LIBC) || defined(RT_USING_MINILIBC) || defined(RT_LIBC_USING_TIME) || (defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 #include <sys/time.h>
 #define LWIP_TIMEVAL_PRIVATE	   0
 #else
@@ -71,10 +71,15 @@
 #define PACK_STRUCT_STRUCT __attribute__ ((__packed__))
 #define PACK_STRUCT_BEGIN
 #define PACK_STRUCT_END
-#elif defined(__IAR_SYSTEMS_ICC__)   /* IAR Compiler */
+#elif defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050) /*Arm Compiler 6*/
+#define PACK_STRUCT_FIELD(x) x
+#define PACK_STRUCT_STRUCT __attribute__((packed))
 #define PACK_STRUCT_BEGIN
-#define PACK_STRUCT_STRUCT
 #define PACK_STRUCT_END
+#elif defined(__IAR_SYSTEMS_ICC__)   /* IAR Compiler */
+#define PACK_STRUCT_BEGIN   #pragma pack(1)
+#define PACK_STRUCT_STRUCT
+#define PACK_STRUCT_END     #pragma pack()
 #define PACK_STRUCT_FIELD(x) x
 #define PACK_STRUCT_USE_INCLUDES
 #elif defined(__GNUC__)     /* GNU GCC Compiler */
diff --git a/include/libc/libc_errno.h b/include/libc/libc_errno.h
index 00c1f733d31a523c62ad1e68d85587d270e7cc95..9143c841f24b059d21f1320d1439a4bf2fb6839f 100644
--- a/include/libc/libc_errno.h
+++ b/include/libc/libc_errno.h
@@ -13,7 +13,7 @@
 
 #include <rtconfig.h>
 
-#if defined(RT_USING_NEWLIB) || defined(_WIN32) || defined( __GNUC__ )
+#if defined(RT_USING_NEWLIB) || defined(_WIN32) || (defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 /* use errno.h file in toolchains */
 #include <errno.h>
 #endif
@@ -45,7 +45,7 @@ defined in armcc/errno.h
 #define ERROR_BASE_NO    0
 #endif
 
-#if !defined(RT_USING_NEWLIB) && !defined(_WIN32) && !defined(__GNUC__ )
+#if !defined(RT_USING_NEWLIB) && !defined(_WIN32) && !(defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 
 #define EPERM            (ERROR_BASE_NO + 1)
 #define ENOENT           (ERROR_BASE_NO + 2)
diff --git a/include/libc/libc_fcntl.h b/include/libc/libc_fcntl.h
index 39740b7d8551498efb9705558920b3be0c206c7f..d149d869646bbb203825303db71e20afad9548ee 100644
--- a/include/libc/libc_fcntl.h
+++ b/include/libc/libc_fcntl.h
@@ -12,7 +12,7 @@
 #ifndef LIBC_FCNTL_H__
 #define LIBC_FCNTL_H__
 
-#if defined(RT_USING_NEWLIB) || defined(_WIN32) || defined( __GNUC__ )
+#if defined(RT_USING_NEWLIB) || defined(_WIN32) || (defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 #include <fcntl.h>
 
 #ifndef O_NONBLOCK
diff --git a/include/libc/libc_fdset.h b/include/libc/libc_fdset.h
index 4a778b51c15884d70bf6509a6e1d68d9344420ab..9700c7e83e6b0f5c36e47fa03c99a4c4360103a0 100644
--- a/include/libc/libc_fdset.h
+++ b/include/libc/libc_fdset.h
@@ -13,7 +13,7 @@
 
 #include <rtconfig.h>
 
-#if defined(RT_USING_NEWLIB) || defined(_WIN32) || defined( __GNUC__ )
+#if defined(RT_USING_NEWLIB) || defined(_WIN32) || (defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 #include <sys/types.h>
 #if defined(HAVE_SYS_SELECT_H)
 #include <sys/select.h>
diff --git a/include/libc/libc_stat.h b/include/libc/libc_stat.h
index 93886885729edf02223ffd847a552f6d510c3c5f..6497cfe12c9ad99ddc0eb46aae9f892647208c08 100644
--- a/include/libc/libc_stat.h
+++ b/include/libc/libc_stat.h
@@ -9,7 +9,7 @@
 
 #include <rtconfig.h>
 
-#if defined(RT_USING_NEWLIB) || defined( __GNUC__ )
+#if defined(RT_USING_NEWLIB) || (defined( __GNUC__ ) && !defined(__ARMCC_VERSION))
 /* use header file of newlib */
 #include <sys/stat.h>