diff --git a/libraries/AP_GPS/examples/GPS_AUTO_test/GPS_AUTO_test.cpp b/libraries/AP_GPS/examples/GPS_AUTO_test/GPS_AUTO_test.cpp
index 168bc5b34e..a137bfc0aa 100644
--- a/libraries/AP_GPS/examples/GPS_AUTO_test/GPS_AUTO_test.cpp
+++ b/libraries/AP_GPS/examples/GPS_AUTO_test/GPS_AUTO_test.cpp
@@ -65,6 +65,7 @@ void setup()
 /*
   print a int32_t lat/long in decimal degrees
  */
+void print_latlon(AP_HAL::BetterStream *s, int32_t lat_or_lon);
 void print_latlon(AP_HAL::BetterStream *s, int32_t lat_or_lon)
 {
     int32_t dec_portion, frac_portion;