diff --git a/src/proto/buffer.pro b/src/proto/buffer.pro
index 509f390..e14ee8f 100644
--- a/src/proto/buffer.pro
+++ b/src/proto/buffer.pro
@@ -33,7 +33,7 @@
 char_u *getaltfname __ARGS((int errmsg));
 int buflist_add __ARGS((char_u *fname, int flags));
 void buflist_slash_adjust __ARGS((void));
-void buflist_altfpos __ARGS((void));
+void buflist_altfpos __ARGS((win_T *win));
 int otherfile __ARGS((char_u *ffname));
 void buf_setino __ARGS((buf_T *buf));
 void fileinfo __ARGS((int fullname, int shorthelp, int dont_truncate));