diff --git a/src/proto/ex_docmd.pro b/src/proto/ex_docmd.pro
index 8505031..2c70eb2 100644
--- a/src/proto/ex_docmd.pro
+++ b/src/proto/ex_docmd.pro
@@ -5,6 +5,7 @@
 int getline_equal(char_u *(*fgetline)(int, void *, int, int), void *cookie, char_u *(*func)(int, void *, int, int));
 void *getline_cookie(char_u *(*fgetline)(int, void *, int, int), void *cookie);
 char_u *getline_peek(char_u *(*fgetline)(int, void *, int, int), void *cookie);
+char *ex_errmsg(char *msg, char_u *arg);
 int parse_command_modifiers(exarg_T *eap, char **errormsg, int skip_only);
 void undo_cmdmod(exarg_T *eap, int save_msg_scroll);
 int parse_cmd_address(exarg_T *eap, char **errormsg, int silent);