diff --git a/components/lwip/api/sockets.c b/components/lwip/api/sockets.c
index 4123712c1..851915877 100755
--- a/components/lwip/api/sockets.c
+++ b/components/lwip/api/sockets.c
@@ -388,9 +388,9 @@ static void lwip_socket_drop_registered_memberships(int s);
 #endif /* LWIP_IGMP */
 
 #ifdef LWIP_ESP8266
-extern size_t system_get_free_heap_size(void);
-extern bool esp_wifi_tx_is_stop(void);
-inline void esp32_tx_flow_ctrl(void)
+//extern size_t system_get_free_heap_size(void);
+//extern bool esp_wifi_tx_is_stop(void);
+static inline void esp32_tx_flow_ctrl(void)
 {
   uint8_t _wait_delay = 0;
 
diff --git a/components/lwip/include/lwip/port/arch/sys_arch.h b/components/lwip/include/lwip/port/arch/sys_arch.h
index 945b4e170..3895f23b3 100644
--- a/components/lwip/include/lwip/port/arch/sys_arch.h
+++ b/components/lwip/include/lwip/port/arch/sys_arch.h
@@ -69,6 +69,8 @@ sys_sem_t* sys_thread_sem_init(void);
 void sys_thread_sem_deinit(void);
 sys_sem_t* sys_thread_sem_get(void);
 
-
+size_t system_get_free_heap_size(void);
+bool esp_wifi_tx_is_stop(void);
+
 #endif /* __SYS_ARCH_H__ */