From d1aa42cd7aa4c3277bf95f84e6f9c4a436bef1cf Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Fri, 19 Jun 2015 01:04:04 +0900
Subject: [PATCH] [bugfix] double close should be safe

---
 extlib/benz/port.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/extlib/benz/port.c b/extlib/benz/port.c
index c73cabd5..5eed06cc 100644
--- a/extlib/benz/port.c
+++ b/extlib/benz/port.c
@@ -188,6 +188,9 @@ pic_get_output_string(pic_state *pic, struct pic_port *port)
 void
 pic_close_port(pic_state *pic, struct pic_port *port)
 {
+  if ((port->flags & PIC_PORT_OPEN) == 0) {
+    return;
+  }
   if (xfclose(port->file) == EOF) {
     pic_errorf(pic, "close-port: failure");
   }