diff --git a/src/proto/terminal.pro b/src/proto/terminal.pro
index 8f2bcd5..2b05d34 100644
--- a/src/proto/terminal.pro
+++ b/src/proto/terminal.pro
@@ -34,4 +34,5 @@
 void f_term_sendkeys(typval_T *argvars, typval_T *rettv);
 void f_term_start(typval_T *argvars, typval_T *rettv);
 void f_term_wait(typval_T *argvars, typval_T *rettv);
+int terminal_enabled(void);
 /* vim: set ft=c : */