Éric Fleming Bonilha wrote:
> Arno
> 
> I use multiple threads to read the data from sockets, I actually have
> a thread pool that process data.

Never done somthing like that, I guess you have to ensure that data is
processed in the right order with such a design, as with Windows IOCP
sockets as well.

> 
> This is my current code for OnDataAvailable from sockets:
> 
> procedure TTCPSocketThread.HandleOnSocketDataAvailable(Sender:
> TObject; ErrCode: Word);
> begin
> 
>   // We can´t proceed on errors
>   if ErrCode <> 0 then
>     Exit;
> 
>   // Start the work
>   ScheduleAction(saReceiveData, 0);
> 
> end;
> 
> So, basically, it does not read the socket, but it schedules an
> action that will be processed by my thread pool system, a thread will
> get the scheduled action and will effectivelly read the socket.
> 
> The problem is that Do_FD_CLOSE will call my
> HandleOnSocketDataAvailable routine, and since that does not read the
> data from socket, the library will enter in an infinite loop, locking
> up my whole system 

[..] 

> Hope you understand the problem I´m facing.

Yes, I understand, but there's a reason for doing this since it 
ensures that OnSessionClosed does not fire until winsock buffer
is empty. 

> 
> To temporarily fix the issue I changed my ICS code to:
> 
> if (FState <> wsConnecting) and (FHSocket <> INVALID_SOCKET) then
>     begin { Check if we have something arrived, if yes, process it   
>     } { DLR, since we are closing MAKE SURE WE LOOP in the receive }
>     { function to get ALL remaining data                         }
>     ASyncReceive(0, FComponentOptions);
> 
> That will call ASyncReceive with flag wsoNoReceiveLoop, allowing me
> not to process the data, because if it is closing the socket I can
> lose the remaining data anyway, this is video data

That may be a workaround in your special case if it doesn't matter
to lose same packets, however that isn't a general solution.
We have the same problem with SSL, where received encrypted data
has to be decrypted first before SessionClosed may be triggered,
the workaround is a derived component that overides Do_FD_Close.

-- 
Arno Garrels


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