diff --git a/src/proto/quickfix.pro b/src/proto/quickfix.pro
index 913c3c4..3a210b0 100644
--- a/src/proto/quickfix.pro
+++ b/src/proto/quickfix.pro
@@ -15,7 +15,7 @@
 void ex_copen(exarg_T *eap);
 void ex_cbottom(exarg_T *eap);
 linenr_T qf_current_entry(win_T *wp);
-int qf_process_qftf_option(void);
+char *qf_process_qftf_option(void);
 int grep_internal(cmdidx_T cmdidx);
 void ex_make(exarg_T *eap);
 int qf_get_size(exarg_T *eap);