diff --git a/src/gpio.c b/src/gpio.c
index 1e2f902..873fd6c 100644
--- a/src/gpio.c
+++ b/src/gpio.c
@@ -194,6 +194,7 @@ int Gpio_read_buttons(void)
     rc |= STATE_BUTTON3;
   if (gpio_input(GLINE_BUTTON4) == 0)
     rc |= STATE_BUTTON4;
+  return rc;
 }
 
 int Gpio_poll_buttons(void)