ldi_add_event_handler - add NDI event service callback handler
#include <sys/ddi_obsolete.h> int ldi_add_event_handler(ldi_handle_t lh, ddi_eventcookie_t ec, void (*handler)(ldi_handle_t, ddi_eventcookie_t, void *, void *) void *arg, ldi_callback_id_t *id);
Layered handle representing event notification device.
Cookie returned from call to ldi_get_eventcookie(9F).
Callback handler for NDI event service notification.
Pointer to opaque data supplied by caller. Typically, this is a pointer to the layered driver's softstate structure.
Pointer to registration id, where a unique registration id is returned. Registration id must be saved and used when calling ldi_remove_event_handler(9F) to unregister a callback handler.
This function is obsolete and is only maintained for compatibility. Use of this function is strongly discouraged. For equivalent functionality provided by new interfaces, see ldi_ev_get_cookie(9F) and ldi_ev_register_callbacks(9F).
The ldi_add_event_handler() function adds a callback handler to be invoked at the occurrence of the event specified by the cookie. Adding a callback handler is also known as subscribing to an event. Upon successful subscription, the handler is invoked when the event occurs. You can unregister the handler by using ldi_remove_event_handler(9F).
An instance of a layered driver can register multiple handlers for an event or a single handler for multiple events. Callback order is not defined and should be assumed to be random.
The routine handler is invoked with the following arguments:
Layered handle representing the device for which the event notification is requested.
Structure describing event that occurred.
Opaque data pointer provided by the driver during callback registration.
Pointer to event specific data defined by the framework that invokes the callback function.
Callback handler registered successfully.
Failed to register callback handler. Possible reasons include lack of resources or a bad cookie.
The ldi_add_event_handler() function can be called from user and kernel contexts only.
Writing Device Drivers
Layered drivers must remove all registered callback handlers for a device instance, represented by the layered handle, by calling ldi_remove_event_handler(9F) before the layered driver's detach(9E) routine completes.