diff --git a/src/proto/fileio.pro b/src/proto/fileio.pro
index 5f1bc75..748bf4c 100644
--- a/src/proto/fileio.pro
+++ b/src/proto/fileio.pro
@@ -33,7 +33,7 @@
 int check_ei(void);
 char_u *au_event_disable(char *what);
 void au_event_restore(char_u *old_ei);
-void do_autocmd(char_u *arg, int forceit);
+void do_autocmd(char_u *arg_in, int forceit);
 int do_doautocmd(char_u *arg, int do_msg, int *did_something);
 void ex_doautoall(exarg_T *eap);
 int check_nomodeline(char_u **argp);