diff --git a/src/proto/buffer.pro b/src/proto/buffer.pro
index 59bb2c2..9e63fb6 100644
--- a/src/proto/buffer.pro
+++ b/src/proto/buffer.pro
@@ -59,6 +59,7 @@
 int bt_quickfix(buf_T *buf);
 int bt_terminal(buf_T *buf);
 int bt_help(buf_T *buf);
+int bt_prompt(buf_T *buf);
 int bt_nofile(buf_T *buf);
 int bt_dontwrite(buf_T *buf);
 int bt_dontwrite_msg(buf_T *buf);