How to use the Uart driver with interrupts

I understand what you're trying to tell me, but from the documentation, the Altera Uart driver should be able to work with interrupts even when using standard I/O functions like printf.

I tried modifying STDOUT like this

	int flags = fcntl(STDOUT_FILENO, F_GETFL);
	fcntl(STDOUT_FILENO, F_SETFL,flags | O_NONBLOCK);
	printf( "Not the stylo venimeux");

But in my simulation waveform the interrupts are not serviced, thus the uart is still working in polling mode even though the Altera driver is supposed to work in non-blocking mode (i.e. using interrupts).

What am I doing wrong?