diff --git a/src/proto/ui.pro b/src/proto/ui.pro
index 4cf87b4..ac830f0 100644
--- a/src/proto/ui.pro
+++ b/src/proto/ui.pro
@@ -2,6 +2,7 @@
 void ui_write(char_u *s, int len);
 void ui_inchar_undo(char_u *s, int len);
 int ui_inchar(char_u *buf, int maxlen, long wtime, int tb_change_cnt);
+int ui_wait_for_chars_or_timer(long wtime, int (*wait_func)(long wtime, int *interrupted, int ignore_input), int *interrupted, int ignore_input);
 int ui_char_avail(void);
 void ui_delay(long msec, int ignoreinput);
 void ui_suspend(void);