Requests the contents of clipboard as the given target. When the results of the result are later received the supplied callback will be called.
An atom representing the form into which the clipboard owner should convert the selection.
A function to call when the results are received (or the retrieval fails). If the retrieval fails the length field of
selection_datawill be negative.
User data to pass to
The argument can be
The data is owned by the caller of the method.