diff --git a/examples/slip-radio/slip-net.c b/examples/slip-radio/slip-net.c
index 4449462e2..28796a1d4 100644
--- a/examples/slip-radio/slip-net.c
+++ b/examples/slip-radio/slip-net.c
@@ -42,7 +42,7 @@
 #define DEBUG 0
 
 /*---------------------------------------------------------------------------*/
-void
+static void
 slipnet_init(void)
 {
 }
@@ -68,7 +68,7 @@ slip_send_packet(const uint8_t *ptr, int len)
   slip_arch_writeb(SLIP_END);
 }
 /*---------------------------------------------------------------------------*/
-void
+static void
 slipnet_input(void)
 {
   int i;