How to read Rotary encoder pulses?

Hi,
I am new to this forum and QT applications. i hope the message is in right place.

i have an ARM9 development board running linux on it. without using GUI i can use all devices on the board like hardware buttons (as interrupts), ADCs, eeproms etc...

For external buttons, ı use this example (simply)

Code:

---

fd = open("/dev/button", 0);
	if (fd < 0) {
		perror("error open device");
		exit(1);
	}
 
	for (;;)
 
{
		char buttons[3];
 
		read(fd, buttons, sizeof buttons);
 printf("%s %s %s", buttons[0] , buttons[1] , buttons[2] );
 
		}

---

this prints the buttons state as 0 or 1

How can i implement this to GUI. how can i read device data continuesly in a fast way? i want to connect a rotary encoder and count the number of pulses. using the console applıcation no problem but how can i make this using QT?

thank you

muisei,
thank you for answering.

i will try to use second method. after some tials i will share the result here.

Use QSocketNotifier on your /dev/button to be notified of changes in the button and only react when there actually is a change. There is no point in having a busy loop (and wasting cpu power and electricity) just for reading the button status.

Quote:

---

Originally Posted by wysota

Use QSocketNotifier on your /dev/button to be notified of changes in the button and only react when there actually is a change. There is no point in having a busy loop (and wasting cpu power and electricity) just for reading the button status.

---

Now i have tried both ways using processevents and Qsocketnotifier.
placing process events in a loop made the application heavy since CPU load
Qsocketnotifier works very good. now i have to check how fast the signals are caught.
here is the part for the code:

Code:

---

buttons_fd = ::open("/dev/buttons", 0);
        QSocketNotifier *sockerNotifier= new QSocketNotifier(buttons_fd,QSocketNotifier::Read,this);
        connect(sockerNotifier,SIGNAL(activated(int)),this,SLOT(notify()));

---

thank you for your help