int reg_ret = alt_iic_isr_register(IRQ_PIO_IRQ_INTERRUPT_CONTROLLER_ID,	// IC_ID
									IRQ_PIO_IRQ,							// IRQ_ID
									&pio_irq_isr,							// Pointer to ISR function
									NULL,									// Pointer to ISR context
									NULL);									// Reserved

	  if(!reg_ret) {
		  printf("Button interrupt service routine (ISR) well registered \n");
	  } else {
		  printf("Something went wrong in the registering; software exits");
		  return 1;
	  }