diff --git a/src/proto/optionstr.pro b/src/proto/optionstr.pro
index 654c935..0d452c2 100644
--- a/src/proto/optionstr.pro
+++ b/src/proto/optionstr.pro
@@ -9,6 +9,6 @@
 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);
-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);
+char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *errbuf, int opt_flags, int *value_checked);
 int check_ff_value(char_u *p);
 /* vim: set ft=c : */