From b76349936b3c923cabf3a3556adc133ea8d3d002 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Fri, 1 Apr 2016 11:30:07 +0900
Subject: [PATCH] [Modify] Add a check

---
 websocket-sharp/Net/HttpListener.cs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/websocket-sharp/Net/HttpListener.cs b/websocket-sharp/Net/HttpListener.cs
index 0b14e9db..8d106411 100644
--- a/websocket-sharp/Net/HttpListener.cs
+++ b/websocket-sharp/Net/HttpListener.cs
@@ -683,7 +683,11 @@ namespace WebSocketSharp.Net
       if (_disposed)
         return;
 
-      close (false);
+      if (_listening) {
+        _listening = false;
+        close (false);
+      }
+
       _disposed = true;
     }