cant catch the Exception in the Concurrency Runtime

Question

Exception thrown at 0x7693483F (KernelBase.dll) in TongJiKeJiVR.exe: WinRT originate error - 0x80072746 : 'An existing connection was forcibly closed by the remote host.'.

Exception thrown at 0x7693483F in TongJiKeJiVR.exe: Microsoft C++ exception: Platform::COMException ^ at memory location 0x1547FB40. HRESULT:0x80072746 An existing connection was forcibly closed by the remote host.

WinRT : An existing connection was forcibly closed by the remote host.

Concurrency::create_task(_writer->StoreAsync()).then(
            [&](Concurrency::task<unsigned int> writeTask)
        {
            try
            {
                // Try getting an exception.
				        writeTask.get();
            }
            catch (...)
            {
                _socket = nullptr;
            }
			});

		
another way i tried
		
		 Concurrency::create_task(_writer->StoreAsync()).then(
            [&](Concurrency::task<unsigned int> writeTask)
        {
            try
            {
                // Try getting an exception.
				        writeTask.get();
            }
            catch (...)
            {
                _socket = nullptr;
            }
			      return writeTask;
			})
			.then([](concurrency::task< unsigned int > t)
		 {
			  try 
			  {
				   t.get();
				   // .get() didn't throw, so we succeeded.
			  }
			  catch (...)
			  {
				     dbg::trace(L" StoreAsync call failed with error2:");
			  }
		});
		
i have found similar question in https://www.it1352.com/486319.html & https://learn.microsoft.com/en-us/cpp/parallel/concrt/exception-handling-in-the-concurrency-runtime?view=msvc-170&redirectedfrom=MSDN
but cant fix my issue with the way in the page

Answer 1

Hi @金旺 王 ,

Welcome to Microsoft Q&A!

I use your code and test it in UWP C++/WinRT project, and the wait() cannot be used in UWP.

If you want to get Exception in concurrency::task<void> t, you need to re-throw the Exception in Concurrency::task<void> previousTask to pass the exception to task t.

Concurrency::create_task(_listener->BindServiceNameAsync("555")).then(
		[this](Concurrency::task<void> previousTask)
		{
			try
			{
				// Try getting an exception.
				// previousTask.get();
				throw ref new Platform::Exception(E_FAIL);
			}
			catch (...)
			{
				OutputDebugString(L"Platform::Exception");
				throw;
			}
			return previousTask;
		}).then([](concurrency::task< void > t)
			{
				try
				{
					t.get();
					// .get() didn't throw, so we succeeded.
				}
				catch (...)
				{
					OutputDebugString(L"Platform::Exception 2");
				}
			}).wait();

Thank you.

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Answer 2

hi Junjie Zhu:

Thanks for your support, I guess i have found the answer, someone has raised the same issue 10 years ago, please refer to below link.

https://social.msdn.microsoft.com/forums/en-US/b55dbfad-6a00-4e42-b481-080fbcfa3ef1/ccx-streamsocket-wrong-ip-or-port-or-connection-error?forum=winappswithnativecode

but i my VS2017 , "If there is a handler for the exception, the program maybe run safety" was deleted