diff --git a/src/proto/typval.pro b/src/proto/typval.pro
index 25ad3e6..9c57226 100644
--- a/src/proto/typval.pro
+++ b/src/proto/typval.pro
@@ -29,4 +29,5 @@
 linenr_T tv_get_lnum(typval_T *argvars);
 linenr_T tv_get_lnum_buf(typval_T *argvars, buf_T *buf);
 buf_T *tv_get_buf(typval_T *tv, int curtab_only);
+buf_T *tv_get_buf_from_arg(typval_T *tv);
 /* vim: set ft=c : */