the source widget.
The targets (data formats) in which the source can provide the data.
A bitmask of the allowed drag actions for this drag.
The button the user clicked to start the drag.
The event that triggered the start of the drag.
the context for this drag. [transfer none]
Warning gtk_drag_begin has been deprecated since version 3.10 and should not be used in newly-written code. Use gtk_drag_begin_with_coordinates() instead. This is equivalent to gtk_drag_begin_with_coordinates(), passing -1, -1 as coordinates.