diff --git a/components/libc/compilers/newlib/libc.h b/components/libc/compilers/newlib/libc.h
index fdf2ab4f60cd30c64ca224c021fa11a3ec1a4834..b4f28e44cc4898f284bf8f2aaee86b8f674b54f7 100644
--- a/components/libc/compilers/newlib/libc.h
+++ b/components/libc/compilers/newlib/libc.h
@@ -34,10 +34,6 @@ 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);
 #ifdef __cplusplus
 }
 #endif