From patchwork Sun Sep 24 10:08:53 2006
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>
X-Patchwork-Id: 12388
Received: from raven.cadsoft.de ([217.7.101.211])
	by www.linuxtv.org with esmtp (Exim 4.50) id 1GRQuv-0007g9-LL
	for vdr@linuxtv.org; Sun, 24 Sep 2006 12:08:57 +0200
Received: from [192.168.100.10] (hawk.cadsoft.de [192.168.100.10])
	by raven.cadsoft.de (8.13.3/8.13.3) with ESMTP id k8OA8uwL032114
	for <vdr@linuxtv.org>; Sun, 24 Sep 2006 12:08:56 +0200
Message-ID: <45165935.3030709@cadsoft.de>
Date: Sun, 24 Sep 2006 12:08:53 +0200
From: Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>
Organization: CadSoft Computer GmbH
User-Agent: Thunderbird 1.5.0.4 (X11/20060516)
MIME-Version: 1.0
To: vdr@linuxtv.org
Subject: Re: [vdr] [RFE] Soft-cancel cThread
References: <45156F49.2070409@gmx.de>
In-Reply-To: <45156F49.2070409@gmx.de>
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0
	(raven.cadsoft.de [192.168.1.1]);
	Sun, 24 Sep 2006 12:08:56 +0200 (CEST)
X-BeenThere: vdr@linuxtv.org
X-Mailman-Version: 2.1.5
Precedence: list
Reply-To: VDR Mailing List <vdr@linuxtv.org>
List-Id: VDR Mailing List <vdr.linuxtv.org>
List-Unsubscribe: <http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr>,
	<mailto:vdr-request@linuxtv.org?subject=unsubscribe>
List-Archive: <http://www.linuxtv.org/pipermail/vdr>
List-Post: <mailto:vdr@linuxtv.org>
List-Help: <mailto:vdr-request@linuxtv.org?subject=help>
List-Subscribe: <http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr>,
	<mailto:vdr-request@linuxtv.org?subject=subscribe>
X-List-Received-Date: Sun, 24 Sep 2006 10:08:57 -0000
Status: O
X-Status: 
X-Keywords: 
X-UID: 10745

Udo Richter wrote:
> Hi,
> 
> I have a suggestion for a VDR change: I could use a way to end a cThread 
> externally without having to wait and without hard canceling it.
> 
> My thread runs with the usual while (Running()) loop. To signal the loop 
> to stop, it would be enough to set running=false. However, running is a 
> private member of cThread. The only way to set running=false is to call 
> Cancel(). This involves killing the thread and waiting for the thread to 
> terminate. Two things I actually don't want.
> 
> There are two ways this could be done. First, by adding a function 
> SoftCancel() { running=false; }. Or second, by modifying Cancel() to 
> just set running=false if called with Cancel(-1) or Cancel(0,false) or 
> similar.

I would prefer using -1 as a special value for this, because this
wouldn't require an interface change.

Does the attached patch do what you want?

Klaus

--- thread.h	2006/01/08 11:40:23	1.36
+++ thread.h	2006/09/24 10:05:41
@@ -103,6 +103,8 @@
        ///< the Action() loop can finish in an orderly fashion and then waiting
        ///< up to WaitSeconds seconds for the thread to actually end. If the
        ///< thread doesn't end by itself, it is killed.
+       ///< If WaitSeconds is -1, only 'running' is set to false and Cancel()
+       ///< returns imemdiately, without killing the thread.
 public:
   cThread(const char *Description = NULL);
        ///< Creates a new thread.
--- thread.c	2006/08/20 10:20:44	1.57
+++ thread.c	2006/09/24 10:04:21
@@ -302,9 +302,11 @@
             }
         esyslog("ERROR: %s thread %d won't end (waited %d seconds) - canceling it...", description ? description : "", childThreadId, WaitSeconds);
         }
-     pthread_cancel(childTid);
-     childTid = 0;
-     active = false;
+     if (WaitSeconds > -1) {
+        pthread_cancel(childTid);
+        childTid = 0;
+        active = false;
+        }
      }
 }