C++
bool isInUse() const;
Description
Returns false if the layer was not in use when AcDbLayerTable::generateUsageData() was last called. Otherwise, returns true.
Usage data is not available (and the function returns true) if the AcDbLayerTableRecord isn't part of an AcDbDatabase or if AcDbLayerTable::generateUsageData() has not been called since this AcDbLayerTableRecord was constructed.