Terminate/Kill Parallel Async after timeout

[chmichael 12]

Hello,

  How can i Terminate/Kill a Parallel.Async ?

 

example:

   Parallel.Async(
      procedure
      begin

         // Call a Winapi Blocking API which take 5000 ms to complete
      end
    );

 

Sleep(1000); //WaitFor 1000ms

 

if MyParallelAsync still running kill it!

 

Thank you

[Vincent Parrett 762]

CancellationTokens are what you need.

 

Parallel.Async as a second optional parameter which is an IOmniTaskConfig - you can create that using the Parallel.TaskConfig class function - then you need to create IOmniCancellationToken  and pass that into the taskConfig.CancelWith - when you want to cancel the async, call cancellationtoken,Signal. 

 

Your procedure can also take an IOmniTask parameter which will give you access to the Cancellation token in your function, so you can gracefully exit

eg 

 

Parallel.Async(
      procedure (const task : IOmniTask)
      begin

         // Call a Winapi Blocking API which take 5000 ms to complete

        if task.CancellationToken.IsSignalled then

          exit.

      end
    );

 

If the blocking api you call takes a handle or array of handles then you can use task.CancellationToken.Handle - eg in calls to WaitForSingleObject or WaitForMultipleObjects 

 

HTH

[chmichael 12]

On 10/11/2020 at 5:07 AM, Vincent Parrett said:

There is no point calling Async with CancellationToken since the above will timeout after 5000ms also!

 

The reason i want to call it Async is because the API has 5000ms timeout and i want to timeout after 2000ms

so in case it's still hasn't timeout i'll kill the async thread!

 

Thank you

 

 

Edited October 12, 2020 by chmichael

[Vincent Parrett 762]

Umm, you might want to edit your reply so it doesn't look like I said it!

 

What is the api you are calling? If an api you are calling is blocking, and doesn't take an event handle or have some way of cancelling then you cannot safely kill it.  Killing a thread on windows is dangerous, 

 

https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-terminatethread

 

[chmichael 12]

On 10/13/2020 at 12:00 AM, Vincent Parrett said:

Umm, you might want to edit your reply so it doesn't look like I said it!

 

What is the api you are calling? If an api you are calling is blocking, and doesn't take an event handle or have some way of cancelling then you cannot safely kill it.  Killing a thread on windows is dangerous, 

 

https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-terminatethread

 

Hello,

  Yes i know but i couldn't find any timeout for this API. It's the Winsock.Connect.

  Do you know how i can use the TerminateThread on Parallel.Async ?

 

Thank you

 

Edited October 19, 2020 by chmichael