--- a/src/chess/rules.h	Thu Apr 16 19:29:11 2026 +0200
+++ b/src/chess/rules.h	Thu Apr 16 19:49:16 2026 +0200
@@ -256,5 +256,14 @@
 uint16_t remaining_movetime(GameInfo *gameinfo, GameState *gamestate,
         uint8_t color);
 
+/**
+ * Converts clock time to string.
+ *
+ * @param time the time to format
+ * @param str the target buffer (should be at least 10 chars large)
+ * @param always_hours if hours should always be printed
+ */
+void print_clk(uint16_t time, char *str, bool always_hours);
+
 #endif	/* RULES_H */