diff --git a/src/proto/ex_docmd.pro b/src/proto/ex_docmd.pro
index 22a0f10..5835db0 100644
--- a/src/proto/ex_docmd.pro
+++ b/src/proto/ex_docmd.pro
@@ -5,6 +5,7 @@
 int getline_equal __ARGS((char_u *(*fgetline)(int, void *, int), void *cookie, char_u *(*func)(int, void *, int)));
 void *getline_cookie __ARGS((char_u *(*fgetline)(int, void *, int), void *cookie));
 int checkforcmd __ARGS((char_u **pp, char *cmd, int len));
+int modifier_len __ARGS((char_u *cmd));
 int cmd_exists __ARGS((char_u *name));
 char_u *set_one_cmd_context __ARGS((expand_T *xp, char_u *buff));
 char_u *skip_range __ARGS((char_u *cmd, int *ctx));