[MonoDevelop] Monitor.Wait return false immediately on Mono Runtime

[Nicolas Krzywinski]

Aah I see the point - sorry I forgot about your writing for the immediate  
output in mono.

I would try to Monitor.Pulse(anotherobject_not_the_lockobject) and  
Monitor.Wait(anotherobject_not_the_lockobject) because it is not  
recommended to use a lock object within the lock area. Just give it a try.

Am 18.09.2011, 19:23 Uhr, schrieb mono <mono at webkai.net>:

> Thank you for reply.
> I understood race condition.
> This code is simplified to understand the problem easily.
>
> I want to know why Moniter.Wait return false before 10 second past.
> Probably it is mono specific.
> I will ask about this problem in mono community.
>
>
>> Ah and what I forgot to mention:
>> For Monitor.Wait(..) to make sense, _I think_ it should not be
>> encapsulated by the lock object is is waiting for - because then it will
>> never return true if the lock object was not pulsed PRIOR to entering  
>> the
>> lock area.
>>
>> Am 18.09.2011, 18:07 Uhr, schrieb Nicolas Krzywinski
>> <opensource at site7even.de>:
>>
>>> Hello,
>>>
>>> you have built a beautiful example of a racing condition.
>>>
>>> Let me explain what your code does in my opinion:
>>>
>>> 1. Spawn thread that executes Async()
>>> 2. Ensleeps this thread for 3 seconds
>>> => Now it is unsure how far the thread was able to execute: is it  
>>> already
>>> sitting on the lock?
>>>
>>> 3. 3 seconds passed, thread is resumed and the Main method as well
>>> => Now it depends on first: the thread already sitting on the lock? and
>>> second: how quickly a thread can be resumed by the runtime?
>>>
>>> ==> Depending on those (multiple) speed conditions either the main  
>>> method
>>> or the thread will reach the lock first!
>>>
>>> Your example shows us that .NET and Mono is implemented different in  
>>> that
>>> case.
>>>
>>> Regards,
>>> 7even
>>>
>>> Am 18.09.2011, 04:49 Uhr, schrieb mono <mono at webkai.net>:
>>>
>>>> Hello
>>>>
>>>> I am using Monodevelop2.6 on Windows Vista.
>>>>
>>>> I build a following code by .NET Runtime.
>>>> Then, 'True' is displayed in 3 second later.
>>>>
>>>> Next, I build by mono2.10.5 runtime.
>>>> And I execute it. But 'False' is displayed in console immediately.
>>>>
>>>> Please, Advice.
>>>>
>>>>
>>>> using System;
>>>> using System.Threading;
>>>>
>>>> namespace MonoThreadTest
>>>> {
>>>>  class MainClass
>>>>  {
>>>>   static object lockObj = new object();
>>>>  public static void Main (string[] args)
>>>>   {
>>>>    new Thread(new ThreadStart(Async)).Start();
>>>>   Thread.Sleep(3 * 1000);
>>>>   lock(lockObj)
>>>>    {
>>>>     Monitor.PulseAll(lockObj);
>>>>    }
>>>>   Console.Read();
>>>>   }
>>>>  static void Async()
>>>>   {
>>>>    lock(lockObj)
>>>>    {
>>>>     Console.WriteLine(Monitor.Wait(lockObj, 10 * 1000));
>>>>    }
>>>>   }
>>>>  }
>>>> }
>>>>
>>>
>>>
>>
>>
>> --
>> www.site7even.de | www.nskcomputing.de
>> _______________________________________________
>> Monodevelop-list mailing list
>> Monodevelop-list at lists.ximian.com
>> http://lists.ximian.com/mailman/listinfo/monodevelop-list
>
> _______________________________________________
> Monodevelop-list mailing list
> Monodevelop-list at lists.ximian.com
> http://lists.ximian.com/mailman/listinfo/monodevelop-list
>


-- 
www.site7even.de | www.nskcomputing.de