From e8fc325e63800e09c1d8f50be8474701b0809e67 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Fri, 1 Apr 2016 11:26:54 +0900
Subject: [PATCH] [Modify] Add a check

---
 websocket-sharp/Net/HttpListener.cs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/websocket-sharp/Net/HttpListener.cs b/websocket-sharp/Net/HttpListener.cs
index 5d89368a..0b14e9db 100644
--- a/websocket-sharp/Net/HttpListener.cs
+++ b/websocket-sharp/Net/HttpListener.cs
@@ -73,7 +73,7 @@ namespace WebSocketSharp.Net
     private Func<IIdentity, NetworkCredential>                   _credFinder;
     private bool                                                 _disposed;
     private bool                                                 _ignoreWriteExceptions;
-    private bool                                                 _listening;
+    private volatile bool                                        _listening;
     private Logger                                               _logger;
     private HttpListenerPrefixCollection                         _prefixes;
     private string                                               _realm;
@@ -630,7 +630,11 @@ namespace WebSocketSharp.Net
       if (_disposed)
         return;
 
-      close (true);
+      if (_listening) {
+        _listening = false;
+        close (true);
+      }
+
       _disposed = true;
     }