[Gambas-user] Socket Limitations

[Kadaitcha Man]

2010/1/3 Doriano Blengino <doriano.blengino at ...1909...>:
> Kadaitcha Man ha scritto:

> After a few minutes I suggested that a timeout could simplify things, I
> changed my mind. It would not be a totally bad idea but, as most other
> mechanisms, it has its problems. First, what is the right timeout?

It is either 0 for no timeout or it is set by the application.

http://msdn.microsoft.com/en-us/library/system.net.sockets.socket.receivetimeout%28VS.80%29.aspx
http://msdn.microsoft.com/en-us/library/system.net.sockets.socket.sendtimeout%28VS.80%29.aspx

$ man socket

       SO_RCVTIMEO and SO_SNDTIMEO
              Specify  the  receiving  or  sending timeouts until reporting an
              error...

perl:
timeout([VAL])
Set or get the timeout value associated with this socket. If called
without any arguments then the current setting is returned. If called
with an argument the current setting is changed and the previous value
returned.

As you can see, the idea of a timeout is not a strange one to many
languages on either Unix, Linux or Windows. In fact, I'd say it is an
absolute necessity. And if you are using the OS socket, which you seem
to be doing, then why should Gambas hide a property that is already
available to C/C++ and even script programmers?

> Second, if a timeout occurs, how many data has been sent?

Again, that is not the business of the socket. The business of the
socket is alert the program that a problem exists, nothing more.

> anyway, this is a truely complicated matter.

It is only complicated if you believe that the socket should poke its
nose into business it shouldn't :)

If the connection goes belly up, the socket can, at best, know how
many bytes it sent into the ether, but it cannot ever know how many of
those bytes went into hyperspace never to be seen again. How can it?
It's not possible. That's why the client and server have to deal with
the problem between themselves.

Really, there is nothing strange in a having timeout. It is up to the
client and the server to work out what to do if the connection goes
down. It is not up to the socket.