diff --git a/src/proto/diff.pro b/src/proto/diff.pro
new file mode 100644
index 0000000..a9fe99e
--- /dev/null
+++ b/src/proto/diff.pro
@@ -0,0 +1,23 @@
+/* diff.c */
+void diff_new_buffer __ARGS((void));
+void diff_buf_delete __ARGS((buf_T *buf));
+void diff_buf_add __ARGS((buf_T *buf));
+void diff_invalidate __ARGS((void));
+void diff_mark_adjust __ARGS((linenr_T line1, linenr_T line2, long amount, long amount_after));
+void ex_diffupdate __ARGS((exarg_T *eap));
+void ex_diffpatch __ARGS((exarg_T *eap));
+void ex_diffsplit __ARGS((exarg_T *eap));
+void ex_diffthis __ARGS((exarg_T *eap));
+void diff_win_options __ARGS((win_T *wp, int addbuf));
+int diff_check __ARGS((win_T *wp, linenr_T lnum));
+int diff_check_fill __ARGS((win_T *wp, linenr_T lnum));
+void diff_set_topline __ARGS((win_T *fromwin, win_T *towin));
+int diffopt_changed __ARGS((void));
+int diff_find_change __ARGS((win_T *wp, linenr_T lnum, int *startp, int *endp));
+int diff_infold __ARGS((win_T *wp, linenr_T lnum));
+void nv_diffgetput __ARGS((int put));
+void ex_diffgetput __ARGS((exarg_T *eap));
+int diff_mode_buf __ARGS((buf_T *buf));
+int diff_move_to __ARGS((int dir, long count));
+linenr_T diff_lnum_win __ARGS((linenr_T lnum, win_T *wp));
+/* vim: set ft=c : */