diff --git a/src/proto/option.pro b/src/proto/option.pro
index 15cf2b4..7d3d8d6 100644
--- a/src/proto/option.pro
+++ b/src/proto/option.pro
@@ -56,4 +56,5 @@
 void save_file_ff __ARGS((buf_T *buf));
 int file_ff_differs __ARGS((buf_T *buf, int ignore_empty));
 int check_ff_value __ARGS((char_u *p));
+long get_sw_value __ARGS((void));
 /* vim: set ft=c : */