Computes the common prefix that is shared by all rows in completion
that start with key. If no row matches key, null will be returned.
Note that a text column must have been set for this function to work,
see gtk.entry_completion.EntryCompletion.setTextColumn for details.
Computes the common prefix that is shared by all rows in completion that start with key. If no row matches key, null will be returned. Note that a text column must have been set for this function to work, see gtk.entry_completion.EntryCompletion.setTextColumn for details.