diff --git a/include/rtc_.h b/include/rtc_.h
index 50b60dd..df359da 100644
--- a/include/rtc_.h
+++ b/include/rtc_.h
@@ -10,7 +10,7 @@
 #include "libbb.h"
 
 extern int rtc_adjtime_is_utc(void);
-extern int rtc_xopen(const char *default_rtc, int flags);
+extern int rtc_xopen(const char **default_rtc, int flags);
 extern time_t rtc_read_time(int fd, int utc);