Re: Advice on abort

["Marc A. Criley" <mcNOSPAM@mckae.com>]

Dmitry A. Kazakov wrote:
> On Tue, 08 Nov 2005 15:54:45 +0100, Poul-Erik Andreasen wrote:
 >
>>I am not that good at sockets, So i vould like to know  wich problematic 
>>(uncleanable) states wee are taking about.
> 
> 
> It all depends on the particular implementation of the socket library and
> how Ada tasks are mapped to system threads and processes. All sorts of
> resource leaks are thinkable. For example, you might be unable to listen
> that TCP/IP port until process restart or it won't abort etc.

When I decided to rework the DTraq socket interface to better handle 
disconnects, loss of comms, response timeouts, and application shutdown 
(and optimize its performance), I tried various approaches that included 
shutting down the socket from a different task and aborting the task 
that was listening on the socket.  As the socket connection was for 
asynchronous communications, I could end up trying to break (or 
experiencing a break in) the connection while it was idling, or while it 
was in the midst of data receipt or data transmission.

Most approaches worked most of the time, but I kept running into 
intermittent glitches.  When I belatedly discovered the selector support 
in GNAT.Sockets, I went with that technique, with the result being no 
more glitches, and a much cleaner implementation.

-- Marc A. Criley
-- McKae Technologies
-- www.mckae.com
-- DTraq - XPath In Ada - XML EZ Out