diff --git a/audio_ao.c b/audio_ao.c
index 51cf3337..62c0729f 100644
--- a/audio_ao.c
+++ b/audio_ao.c
@@ -43,6 +43,7 @@ static void help(void) {
 static int init(int argc, char **argv) {
   const char *str;
   int value;
+  double dvalue;
   ao_initialize();
   int driver = ao_default_driver_id();
   ao_option *ao_opts = NULL;