diff --git a/src/proto/ops.pro b/src/proto/ops.pro
index 1e89c4e..8a25bf6 100644
--- a/src/proto/ops.pro
+++ b/src/proto/ops.pro
@@ -17,7 +17,7 @@
 void op_addsub(oparg_T *oap, linenr_T Prenum1, int g_cmd);
 void clear_oparg(oparg_T *oap);
 void cursor_pos_info(dict_T *dict);
-int set_operatorfunc_option(void);
+char *set_operatorfunc_option(void);
 void free_operatorfunc_option(void);
 int set_ref_in_opfunc(int copyID);
 void do_pending_operator(cmdarg_T *cap, int old_col, int gui_yank);