diff --git a/src/proto/optionstr.pro b/src/proto/optionstr.pro
new file mode 100644
index 0000000..dc1079e
--- /dev/null
+++ b/src/proto/optionstr.pro
@@ -0,0 +1,14 @@
+/* optionstr.c */
+void didset_string_options(void);
+void trigger_optionsset_string(int opt_idx, int opt_flags, char_u *oldval, char_u *oldval_l, char_u *oldval_g, char_u *newval);
+char *did_set_string_option(int opt_idx, char_u **varp, int new_value_alloced, char_u *oldval, char *errbuf, int opt_flags, int *value_checked);
+void check_buf_options(buf_T *buf);
+void free_string_option(char_u *p);
+void clear_string_option(char_u **pp);
+void check_string_option(char_u **pp);
+void set_string_option_direct(char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
+void set_string_option_direct_in_win(win_T *wp, char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
+void set_string_option_direct_in_buf(buf_T *buf, char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
+char *set_string_option(int opt_idx, char_u *value, int opt_flags);
+int check_ff_value(char_u *p);
+/* vim: set ft=c : */