void (*buttslot[BUTTONS_SLOTS])(uint8_t)

#define BUTTONS_SLOTS 3
.......................................

void Buttons::search(uint32_t time){//Tmanager function
	uint8_t slots = BUTTONS_SLOTS;
	uint8_t buttonscurrstate = buttonsState();
	//update buttons every some time, with overflow prevention
	if (abs(time - lastupdatetime) > updatetime){
		if (buttonscurrstate)//if any button was pressed
		{ //check all buttons slot
			for (uint8_t buttonslot = 0; buttonslot < slots ; buttonslot++)
			{//detect edge only
				if ((buttonscurrstate & (1 << buttonslot)) && (!(buttonoldstate & (1 << buttonslot))))
				{
					if (buttslot[buttonslot]);
					{
						(*buttslot[buttonslot])(buttonscurrstate&(1 << buttonslot));
					}
				}
			}
		}
		buttonoldstate = buttonscurrstate;//save old state
		lastupdatetime = time;
	}
}