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 DDI_ADD_EVENT_HANDLER 9F "Nov 26, 2017"
 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
illumos DDI specific (illumos 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 specified 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(7) for a description of the following attributes:






ATTRIBUTE TYPE ATTRIBUTE VALUE
Stability Level Committed



 SEE ALSO
 attributes (7),  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.