Re: [GD-Windows] Limiting to one instance
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Re: [GD-Windows] Limiting to one instance
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From: Dirk R. <ri...@ph...> - 2006-08-15 08:22:16
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One thing to keep in mind when using global objects in windows is Fast = User Switching in Windows XP, where in fact multiple users are logged in = at the same time. When you use CreateMutex you block the application = from running under ALL other user accounts as well. This could as well = apply to FindWindow. If you do not want this to happen, you have to use = a technique which is per user, like the old unix style pid file stored = under the users home directory. Dirk -----Urspr=FCngliche Nachricht----- Von: gam...@li... = [mailto:gam...@li...] Im Auftrag = von Alen Ladavac Gesendet: Dienstag, 15. August 2006 10:13 An: Andrew Grant Cc: Game Development for MS Windows Betreff: Re: [GD-Windows] Limiting to one instance > I remember at an old company one genius tried to prevent multiple = instances > of an app by binding a port, and was then surprised when it failed for > pretty much everyone who was running a firewall! Actually, it's not such a weird idea. Some applications rely on IP ports as a simple yet very portable IPC mechanism. Firewalls should really know better, by handling 127.0.0.1 specifically by default. But apparently even the best in class don't. Btw, in my book, even using a named mutex in that way is a bit hacky because you are relying on error. But what can we do, when there's no real API intended for that purpose. Personally, I've been using FindWindow(xyz, NULL) to find a main window by class name. Same principle (with same weaknesses as a named mutex), but doesn't require an extra object creation, as you probably already have a window, and you can use this to test even for foreign applications, because it doesn't require access to the code of the tested application. A nice side effect is that once you have the window, you can report messages like "Cannot start, please close ABCD application first", where you get the ABCD from the application's main window caption. Cheers, Alen -------------------------------------------------------------------------= Using Tomcat but need to do more? Need to support web services, = security? Get stuff done quickly with pre-integrated technology to make your job = easier Download IBM WebSphere Application Server v.1.0.1 based on Apache = Geronimo http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D120709&bid=3D263057&dat=3D= 121642 _______________________________________________ Gamedevlists-windows mailing list Gam...@li... https://lists.sourceforge.net/lists/listinfo/gamedevlists-windows Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=3D555 |
