[C++] how to execute some action after "x" seconds of keyboard inactivity?

[fbs777]

Hi.

Im trying to execute some actions when there's no keyboard action in "x" seconds or minutes (after "x" seconds or minutes of keyboard inactivity), but is hard to find something about this...

and i dont know if this will make a lot of cpu usage

[GNU-Fan]

This is what the powermanager/screensaver from Gnome/KDE/etc. basically does. So I would look how they do it.

[Rubberman]

GNU-Fan's suggestion is reasonable is you are talking about a system where the USER is running an X-Windows desktop (KDE, Gnome, XFCE, etc). It really depends a lot on the environment. As for CPU utilization, it should not be an issue, unless you use a polling construct to detect the keypress. Normally this would be an event-driven handler. It sounds like you need to do some studying of how to deal with hardware asyncronous events in user-space programs.

[fbs777]

im using fluxbox, no kde/gnome. and no user, just root (its an embeeded linux)

[Rubberman]

Well, in that case I would download the fluxbox source and see what they do to trigger the screen saver. Since it is an X-Windows application, they undoubtedly trap keypress events anywhere on the screen to reset the timer. It's not that hard to do with low-level Xlib functions, but then it isn't trivial either. Basically, you need a timer that will start your program when it expires, and a kepress XEvent handler that will reset the timer when it detects a keypress anywhere on the screen.

The source for fluxbox is available here: fluxbox.org - download