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digitalmars.D.learn - looking for Socket.select with maximum time or other solution

reply Charma <Motoko_Kusanagi web.de> writes:
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?

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

Thanks for any suggestions and help!!
Sorry about my engrish!!

Charma
Oct 07 2007
next sibling parent Nathan Reed <nathaniel.reed gmail.com> writes:
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.


I'd use a separate thread for that.


 Also i would like to know: Is there any way i can cancel socket.select 
 while it is waiting? I mean, i would like to be able to quit my server 
 clean without needing to connect with a client again and so on...


How about, from another thread, killing the thread that is running 
select?  Yeah, a little bit clumsy, but at least you don't have to kill 
the process from the console.

Thanks,
Nathan Reed
Oct 07 2007
prev sibling parent reply Regan Heath <regan netmail.co.nz> writes:
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
Oct 08 2007
parent Charma <Motoko_Kusanagi web.de> writes:
Regan Heath schrieb:

 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


Regan,
As usual, you had exactly what i was looking for! For some reason, i 
don't know by myself, i was always overlooking that there exists a 
parameter for that...
Thanks a lot! This solves my problem :)

I want to avoid using threads to keep my server as fast and efficient as 
possible, so i will try to come up with something for a completly 
seperate connection which will be handled different from the other 
clients...

Greetings,
Charma
Oct 08 2007