diff --git a/src/proto/terminal.pro b/src/proto/terminal.pro
index 7b28c28..a004d35 100644
--- a/src/proto/terminal.pro
+++ b/src/proto/terminal.pro
@@ -17,6 +17,7 @@
 int term_get_attr(buf_T *buf, linenr_T lnum, int col);
 char_u *term_get_status_text(term_T *term);
 int set_ref_in_term(int copyID);
+void f_term_getaltscreen(typval_T *argvars, typval_T *rettv);
 void f_term_getattr(typval_T *argvars, typval_T *rettv);
 void f_term_getcursor(typval_T *argvars, typval_T *rettv);
 void f_term_getjob(typval_T *argvars, typval_T *rettv);