diff --git a/components/libc/compilers/armlibc/libc.h b/components/libc/compilers/armlibc/libc.h
index 38d72241d5..b9b1b6212d 100644
--- a/components/libc/compilers/armlibc/libc.h
+++ b/components/libc/compilers/armlibc/libc.h
@@ -15,12 +15,12 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-    int libc_system_init(void);
+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_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);
+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);
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/libc/compilers/dlib/libc.h b/components/libc/compilers/dlib/libc.h
index a3a5753c77..5b46bee0c8 100644
--- a/components/libc/compilers/dlib/libc.h
+++ b/components/libc/compilers/dlib/libc.h
@@ -16,12 +16,12 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-    int libc_system_init(void);
+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_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);
+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);
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/libc/compilers/newlib/libc.h b/components/libc/compilers/newlib/libc.h
index e2613740b9..fdf2ab4f60 100644
--- a/components/libc/compilers/newlib/libc.h
+++ b/components/libc/compilers/newlib/libc.h
@@ -30,14 +30,14 @@
 #ifdef __cplusplus
 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_system_init(void);
+int libc_stdio_set_console(const char* device_name, int mode);
+int libc_stdio_get_console(void);
 
-    /* some time related function */
-    int libc_set_time(const struct timespec* time);
-    int libc_get_time(struct timespec* time);
-    int libc_time_to_tick(const struct timespec* time);
+/* some time related function */
+int libc_set_time(const struct timespec* time);
+int libc_get_time(struct timespec* time);
+int libc_time_to_tick(const struct timespec* time);
 #ifdef __cplusplus
 }
 #endif