ddi_add_event_handler(9F)				   Kernel Functions for Drivers 				 ddi_add_event_handler(9F)

NAME

       ddi_add_event_handler - add an NDI event service callback handler

SYNOPSIS

       #include <sys/dditypes.h>
       #include <sys/sunddi.h>

       int ddi_add_event_handler(dev_info_t *dip, ddi_eventcookie_t cookie, void (*handler)(dev_info_t *, ddi_eventcookie_t, void *, void *), void
       *arg, ddi_registration_id_t *id);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI).

PARAMETERS

       dev_info_t *dip

	   Device node registering the callback.

       ddi_eventcookie_t cookie

	   Cookie returned from call to ddi_get_eventcookie(9F).

       void (*handler)(dev_info_t *, ddi_eventcookie_t, void *, void *)

	   Callback handler responsible for handling an NDI event service notification.

       void *arg

	   Pointer to opaque data supplied by the caller. Typically, this would be a pointer to the driver's softstate structure.

       ddi_registration_id_t *id

	   Pointer to registration ID where a unique registration id will be returned. Registration  ID  must  be  saved  and  used  when  calling
	   ddi_remove_event_handler(9F) to unregister a callback.

DESCRIPTION

       The  ddi_add_event_handler()  function  adds  a	callback handler to be invoked in the face of the event specifed by cookie. The process of
       adding a callback handler is also known as subscribing to an event. Upon successful subscription, the handler will be invoked by the system
       when the event occurs. The handler can be unregistered by using ddi_remove_event_handler(9F).

       An  instance of a driver can register multiple handlers for an event or a single handler for multiple events. Callback order is not defined
       and should assumed to be random.

       The routine handler will be invoked with the following arguments:

       dev_info_t *dip

	   Device node requesting the notification.

       ddi_eventcookie_t cookie

	   Structure describing event that occurred.

       void *arg

	   Opaque data pointer provided, by the driver, during callback registration.

       void *impl_data

	   Pointer to event specific data defined by the framework which invokes the callback function.

RETURN VALUES

       DDI_SUCCESS

	   Callback handler registered successfully.

       DDI_FAILURE

	   Failed to register callback handler. Possible reasons include lack of resources or a bad cookie.

CONTEXT

       The ddi_add_event_handler() and handler() function can be called from user and kernel contexts only.

ATTRIBUTES

       See attributes(5) for a description of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Stability Level 	     |Evolving			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       attributes(5), ddi_get_eventcookie(9F), ddi_remove_event_handler(9F)

       Writing Device Drivers

NOTES

       Drivers must remove all registered callback handlers for a device instance by calling ddi_remove_event_handler(9F) before detach completes.

SunOS 5.10							    62 Nov 2003 					 ddi_add_event_handler(9F)