Control Routine Installation and Examination

To install an interrupt handler, use InstallInterruptFunctions. This routine replaces the earlier Slot Manager routine SIntInstall. After an ISR has been installed, GetInterruptFunctions lets you examine it.

IMPORTANT

ISR functions are never explicitly removed. To deregister an ISR, reinstall the ISR function that was obtained by means of the GetInterruptFunctions routine before the ISR was originally installed. Then call the IST disabler function to keep any further interrupts from requesting service.

The declarations for the interrupt handler, enabler, and disabler are the following:



 
typedef InterruptMemberNumber   (*InterruptHandler)

                                (InterruptSetMember ISTmember,

                                 void *              refCon,

                                UInt32              theIntCount);



 
typedef void            (*InterruptEnabler)

                        (InterruptSetMember member,

                         void *             refCon);



 
typedef InterruptSourceState    (*InterruptDisabler) 

                                (InterruptSetMember member,

                                void *              refCon);

The interrupt set ID and interrupt member number values are available as driver-ist properties associated with each device entry in the Name Registry. Hardware, secondary, and software interrupt mechanisms are described in Interrupt Management.