diff --git a/src/term.c b/src/term.c
index a13959b..b61667d 100644
--- a/src/term.c
+++ b/src/term.c
@@ -100,7 +100,7 @@
     // Change this to "if 1" to debug what happens with termresponse.
 #  if 0
 #   define DEBUG_TERMRESPONSE
-static void log_tr(const char *fmt, ...);
+static void log_tr(const char *fmt, ...) ATTRIBUTE_FORMAT_PRINTF(1, 2);
 #   define LOG_TR(msg) log_tr msg
 #  else
 #   define LOG_TR(msg) do { /**/ } while (0)