Aborting a call to Accept_Socket

[Tony <truand.tony@gmail.com>]

I would like to abort a call to Accept_Socket() if no connection
request arrives within a specified time (20 seconds).  For me, a quite
simple solution (perhaps not safe) is to use an asynchronous transfer
of control like this:
--****************************************************
   procedure Server is
       ...
   begin
       GNAT.Sockets.Initialize;
       ...
       loop
           ...
           select
               delay 20.0;
               exit;
           then abort
               GNAT.Sockets.Accept_Socket (...);
           end select;
           ...
       end loop ;
   end Server;
--****************************************************
The expecting behaviour was the end of the program after 20 seconds
(if no connection request arrives). I observe : after 20 seconds the
program will terminate only if  a connection request arrives.
Is this behaviour correct?
Thanks.