looking for Socket.select with maximum time or other solution

[Regan Heath]

Charma wrote:
> Hello everyone!
> I am currently working on a server which many clients can connect to and 
> i am using socket.select with my socketset which all clients are in. 
> This far everything works very fine. But i would prefer my server-loop 
> to continue e.g. at least 10 times every second to work on other things 
> even when nothing is send from clients.
> 
> Is there anything i can do to force socket.select to stop waiting after 
> a given time even if all sockets will stay as marked with nothing to 
> receive?

This version of select takes a timeout parameter of type timeval:

static int select(SocketSet checkRead, SocketSet checkWrite, SocketSet 
checkError, timeval* tv);

you will need to reload the sockets into the set before every call.

> Maybe someone has an even better/other/different idea?!?
> 
> Also i would like to know: Is there any way i can cancel socket.select 
> while it is waiting? 

I believe you could interrupt it from another thread but I don't think 
that it is necessary, simply use a short timeout period and make the 
main loop check a termination variable eg.

while(!timeToStop)
{
   select...with short timeout.
}

Of course, you need some method of setting timeToStop, perhaps you check 
for keyboard input in the main loop, perhaps a client connection 
processes a command like "shutdown"...

You can use a ticker/counter variable in the main loop to restrict how 
often certain tasks are carried out, eg.

ticker=0
while(!timeToStop)
{
   select...with timeout of 100ms (10x/sec)
   if (ticker%5 == 0) { //2x/sec
     //put stuff in here that only happens 2x/sec
   }
   ..etc..
}

It may be a cleaner design, and better in the multi-cpu enviroment we 
have today to create a thread for each task, where the thread simply 
sleeps between tasks.

 > I mean, i would like to be able to quit my server
> clean without needing to connect with a client again and so on...

In that case perhaps a check for keyboard input is what you want.

Regan