This method checks recursively whether an object is current.
The IsUpToDate method provides a way for containers to check recursively whether all objects are up to date. That is, when the container calls this method on the first object, the object in turn calls it for all its own objects, and they in turn for all of theirs, until all objects have been checked.
To determine whether the platform supports this interface, see Determining Supported COM APIs.
Because of the recursive nature of IsUpToDate, determining whether an object is out-of-date, particularly one that contains one or more other objects, can be as time-consuming as updating the object.
To avoid lengthy queries of this type, make sure IsUpToDate returns OLE_E_UNAVAILABLE.
When the object to be queried is small and contains no objects itself, which makes an efficient query possible, this method can return either S_OK or S_FALSE.