Sleep - SystemSleepResult class

wakeupPin() (SystemSleepResult)

SystemSleepResult::wakeupPin, wakeupPin, SystemSleepResult.wakeupPin

// PROTOTYPE
pin_t wakeupPin() const;

If wakeupReason() is SystemSleepWakeupReason::BY_GPIO returns which pin caused the wake. See example under wakeupReason(), above.