How do you keep the machine awake?

Question

I have a piece of server-ish software written in Java to run on Windows and OS X. (It is not running on a server, but just a normal user's PC - something like a torrent client.) I would like the software to signal to the OS to keep the machine awake (prevent it from going into sleep mode) while it is active.

Of course I don't expect there to be a cross platform solution, but I would love to have some very minimal C programs/scripts that my app can spawn to inform the OS to stay awake.

Any ideas?

Answer 1

I use this code to keep my workstation from locking. It's currently only set to move the mouse once every minute, you could easily adjust it though.

It's a hack, not an elegant solution.

import java.awt.*; import java.util.*; public class Hal{      public static void main(String[] args) throws Exception{         Robot hal = new Robot();         Random random = new Random();         while(true){             hal.delay(1000 * 60);             int x = random.nextInt() % 640;             int y = random.nextInt() % 480;             hal.mouseMove(x,y);         }     } } 

Answer 2

On Windows, use the SystemParametersInfo function. It's a Swiss army-style function that lets you get/set all sorts of system settings.

To disable the screen shutting off, for instance:

SystemParametersInfo( SPI_SETPOWEROFFACTIVE, 0, NULL, 0 ); 

Just be sure to set it back when you're done...