diff --git a/src/proto/memline.pro b/src/proto/memline.pro
index bddb902..727b24c 100644
--- a/src/proto/memline.pro
+++ b/src/proto/memline.pro
@@ -34,4 +34,5 @@
 void ml_decrypt_data(memfile_T *mfp, char_u *data, off_T offset, unsigned size);
 long ml_find_line_or_offset(buf_T *buf, linenr_T lnum, long *offp);
 void goto_byte(long cnt);
+char_u *make_percent_swname (char_u *dir, char_u *name);
 /* vim: set ft=c : */