diff --git a/finsh/cmd.c b/finsh/cmd.c
index f7903941600b2c389d2e49242f43795b023135cf..c6ea09ad00f769c70d5a4068d13e8b22273dcbae 100644
--- a/finsh/cmd.c
+++ b/finsh/cmd.c
@@ -369,7 +369,7 @@ int list()
 }
 FINSH_FUNCTION_EXPORT(list, list all symbol in system)
 
-int str_is_prefix(const char* prefix, const char* str)
+static int str_is_prefix(const char* prefix, const char* str)
 {
 	while ((*prefix) && (*prefix == *str))
 	{