From 3d0657074fbaa6f6bee6533193728c097e1e313f Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Sun, 9 Feb 2014 02:41:20 +0900
Subject: [PATCH] first argument of get-output-string is optinoal

---
 src/port.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/port.c b/src/port.c
index 7e934dae..2ee95807 100644
--- a/src/port.c
+++ b/src/port.c
@@ -262,11 +262,11 @@ pic_port_open_output_string(pic_state *pic)
 static pic_value
 pic_port_get_output_string(pic_state *pic)
 {
-  struct pic_port *port;
+  struct pic_port *port = pic_stdout(pic);;
   long endpos;
   char *buf;
 
-  pic_get_args(pic, "p", &port);
+  pic_get_args(pic, "|p", &port);
 
   assert_port_profile(port, PIC_PORT_OUT | PIC_PORT_TEXT, PIC_PORT_OPEN, "read-char");