diff --git a/tools/sdk/include/sntp.h b/tools/sdk/include/sntp.h
index bb85e678b..23275f182 100644
--- a/tools/sdk/include/sntp.h
+++ b/tools/sdk/include/sntp.h
@@ -18,7 +18,7 @@ uint32 sntp_get_current_timestamp();
 /**
  * get real time (GTM + 8 time zone)
  */
-char* sntp_get_real_time(long t);
+char* sntp_get_real_time(time_t t);
 /**
  * SNTP get time_zone default GMT + 8
  */