Instance Property

queryElementValue

Obtains the current value of an element.

Declaration

IOReturn (*queryElementValue)(void *self, IOHIDElementCookie elementCookie, IOHIDEventStruct *valueEvent, uint32_t timeoutMS, IOHIDElementCallbackFunction callback, void *callbackTarget, void *callbackRefcon);

Parameters

elementCookie

The element of interest.

valueEvent

The event that will be filled. If a long value is present, it is up to the caller to deallocate it.

timeoutMS

UNSUPPORTED.

callback

UNSUPPORTED.

callbackTarget

UNSUPPORTED.

callbackRefcon

UNSUPPORTED.

Return Value

Returns an IOReturn code.

Discussion

This call is most useful for feature type elements. This method will poll the device for the current element value.