Perform a single undo. Calling this function when there are no undo operations available is an error. Use gtk_source_undo_manager_can_undo() to find out if there are undo operations available.
2.10
See Implementation
Perform a single undo. Calling this function when there are no undo operations available is an error. Use gtk_source_undo_manager_can_undo() to find out if there are undo operations available.