The callback function takes the following arguments: event type (int),
GPIO line offset (unsigned int), event timestamp (const struct timespec *)
and a pointer to user data (void *).
This callback is called by the ctxless event loop functions for each GPIO
event. If the callback returns ::GPIOD_CTXLESS_EVENT_CB_RET_ERR, it should
also set errno.
@brief Simple event callback signature.
The callback function takes the following arguments: event type (int), GPIO line offset (unsigned int), event timestamp (const struct timespec *) and a pointer to user data (void *).
This callback is called by the ctxless event loop functions for each GPIO event. If the callback returns ::GPIOD_CTXLESS_EVENT_CB_RET_ERR, it should also set errno.