The GetDataHandler function allows you to retrieve the best data handler component to use with a given data reference.
pascal Component GetDataHandler (Handle dataRef, OSType dataHandlerSubType, long
flags);
Once you have used this function to get information about the best data handler component for your data reference, you can open and use the component using Component Manager functions. See "Data Handler Components," for more information.
If the function returns a value of nil , the Movie Toolbox was unable to find an appropriate data handler component. For more information about the error, call the GetMoviesError Movie Toolbox function.