diff --git a/components/libc/compilers/armlibc/libc.h b/components/libc/compilers/armlibc/libc.h
index aecf8cdc50..5c1613728e 100644
--- a/components/libc/compilers/armlibc/libc.h
+++ b/components/libc/compilers/armlibc/libc.h
@@ -10,17 +10,14 @@
 #ifndef __RTT_LIBC_H__
 #define __RTT_LIBC_H__
 
-#include <stddef.h>
-
 #ifdef __cplusplus
 extern "C" {
 #endif
-int libc_system_init(void);
 
-int libc_stdio_set_console(const char* device_name, int mode);
+int libc_system_init(void);
 int libc_stdio_get_console(void);
-int libc_stdio_read(void* buffer, size_t size);
-int libc_stdio_write(const void* buffer, size_t size);
+int libc_stdio_set_console(const char* device_name, int mode);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/libc/compilers/armlibc/stdio.c b/components/libc/compilers/armlibc/stdio.c
index c786c78aa5..7dd9dbfe3f 100644
--- a/components/libc/compilers/armlibc/stdio.c
+++ b/components/libc/compilers/armlibc/stdio.c
@@ -21,6 +21,7 @@
 #define STDIO_DEVICE_NAME_MAX   32
 
 static int std_fd = -1;
+
 int libc_stdio_set_console(const char* device_name, int mode)
 {
     int fd;
@@ -47,29 +48,4 @@ int libc_stdio_get_console(void)
     return std_fd;
 }
 
-int libc_stdio_read(void *buffer, size_t size)
-{
-    if (std_fd >= 0)
-    {
-        return read(std_fd, buffer, size);
-    }
-    else
-    {
-        rt_kprintf("Illegal stdio input!\n");
-        return 0;
-    }
-}
-
-int libc_stdio_write(const void *buffer, size_t size)
-{
-    if (std_fd >= 0)
-    {
-        return write(std_fd, buffer, size);
-    }
-    else
-    {
-        rt_kprintf("Illegal stdio output!\n");
-        return size;
-    }
-}
 #endif
diff --git a/components/libc/compilers/armlibc/syscalls.c b/components/libc/compilers/armlibc/syscalls.c
index be6041a663..d942bdb984 100644
--- a/components/libc/compilers/armlibc/syscalls.c
+++ b/components/libc/compilers/armlibc/syscalls.c
@@ -146,16 +146,17 @@ int _sys_read(FILEHANDLE fh, unsigned char *buf, unsigned len, int mode)
     if (fh == STDIN)
     {
 #ifdef RT_USING_POSIX
-        size = libc_stdio_read(buf, len);
+        size = read(STDIN_FILENO, buf, len);
         return len - size;
 #else
         /* no stdin */
         return -1;
 #endif
     }
-
-    if ((fh == STDOUT) || (fh == STDERR))
+    else if ((fh == STDOUT) || (fh == STDERR))
+    {
         return -1;
+    }
 
 #ifndef RT_USING_DFS
     return 0;
@@ -185,7 +186,7 @@ int _sys_write(FILEHANDLE fh, const unsigned char *buf, unsigned len, int mode)
         return 0;
 #else
 #ifdef RT_USING_POSIX
-        size = libc_stdio_write(buf, len);
+        size = write(STDOUT_FILENO, buf, len);
         return len - size;
 #else
         if (rt_console_get_device())
@@ -198,8 +199,10 @@ int _sys_write(FILEHANDLE fh, const unsigned char *buf, unsigned len, int mode)
 #endif
 #endif
     }
-
-    if (fh == STDIN) return -1;
+    else if (fh == STDIN)
+    {
+        return -1;
+    }
 
 #ifndef RT_USING_DFS
     return 0;
diff --git a/components/libc/compilers/dlib/libc.h b/components/libc/compilers/dlib/libc.h
index fc3cafca78..9643c1161f 100644
--- a/components/libc/compilers/dlib/libc.h
+++ b/components/libc/compilers/dlib/libc.h
@@ -11,17 +11,14 @@
 #ifndef __RTT_LIBC_H__
 #define __RTT_LIBC_H__
 
-#include <stddef.h>
-
 #ifdef __cplusplus
 extern "C" {
 #endif
-int libc_system_init(void);
 
-int libc_stdio_set_console(const char* device_name, int mode);
+int libc_system_init(void);
 int libc_stdio_get_console(void);
-int libc_stdio_read(void* buffer, size_t size);
-int libc_stdio_write(const void* buffer, size_t size);
+int libc_stdio_set_console(const char* device_name, int mode);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/libc/compilers/dlib/stdio.c b/components/libc/compilers/dlib/stdio.c
index c11157d759..ed3f5dfef9 100644
--- a/components/libc/compilers/dlib/stdio.c
+++ b/components/libc/compilers/dlib/stdio.c
@@ -46,13 +46,4 @@ int libc_stdio_get_console(void) {
     return std_fd;
 }
 
-int libc_stdio_read(void *buffer, size_t size)
-{
-    return read(std_fd, buffer, size);
-}
-
-int libc_stdio_write(const void *buffer, size_t size)
-{
-    return write(std_fd, buffer, size);
-}
 #endif
diff --git a/components/libc/compilers/dlib/syscall_read.c b/components/libc/compilers/dlib/syscall_read.c
index afb661bd93..e716d0b024 100644
--- a/components/libc/compilers/dlib/syscall_read.c
+++ b/components/libc/compilers/dlib/syscall_read.c
@@ -25,14 +25,15 @@ size_t __read(int handle, unsigned char *buf, size_t len)
     if (handle == _LLIO_STDIN)
     {
 #ifdef RT_USING_POSIX
-        return libc_stdio_read(buf, len);
+        return read(STDIN_FILENO, buf, len);
 #else
         return _LLIO_ERROR;
 #endif
     }
-
-    if ((handle == _LLIO_STDOUT) || (handle == _LLIO_STDERR))
+    else if ((handle == _LLIO_STDOUT) || (handle == _LLIO_STDERR))
+    {
         return _LLIO_ERROR;
+    }
 
 #ifndef RT_USING_DFS
     return _LLIO_ERROR;
diff --git a/components/libc/compilers/dlib/syscall_write.c b/components/libc/compilers/dlib/syscall_write.c
index de464530b8..a5462653bf 100644
--- a/components/libc/compilers/dlib/syscall_write.c
+++ b/components/libc/compilers/dlib/syscall_write.c
@@ -30,19 +30,24 @@ size_t __write(int handle, const unsigned char *buf, size_t len)
 #else
 
 #ifdef RT_USING_POSIX
-        return libc_stdio_write((void*)buf, len);
+        return write(STDOUT_FILENO, (void*)buf, len);
 #else
         rt_device_t console_device;
 
         console_device = rt_console_get_device();
-        if (console_device != 0) rt_device_write(console_device, 0, buf, len);
+        if (console_device != 0)
+        {
+            rt_device_write(console_device, 0, buf, len);
+        }
 
         return len;
 #endif
 #endif
     }
-
-    if (handle == _LLIO_STDIN) return _LLIO_ERROR;
+    else if (handle == _LLIO_STDIN)
+    {
+        return _LLIO_ERROR;
+    }
 
 #ifndef RT_USING_DFS
     return _LLIO_ERROR;
diff --git a/components/libc/compilers/newlib/libc.h b/components/libc/compilers/newlib/libc.h
index c1f76d7605..c470698aa6 100644
--- a/components/libc/compilers/newlib/libc.h
+++ b/components/libc/compilers/newlib/libc.h
@@ -18,8 +18,8 @@
 extern "C" {
 #endif
 int libc_system_init(void);
-int libc_stdio_set_console(const char* device_name, int mode);
 int libc_stdio_get_console(void);
+int libc_stdio_set_console(const char* device_name, int mode);
 
 #ifdef __cplusplus
 }