keypad functionality implementation using egl calls

Hi i am trying to handle key press events using egl calls and xrandr libraries. i need only few key board events to work like s, h, q and escape. Presently my code works for s,h,q and escape. But it also works for print screen key and alt key. when i press print screen key, a screen shot is being captured which i don't need. i tried searching the key codes for print screen and alt key and disabling it in my code. But when i run the code, nothing has changed and screen shot is getting captured.