gdk:display-store-clipboard (display window time targets)

display -- a gdk:display object
window -- a gdk:window object belonging to the clipboard owner
time -- an unsigned integer for the timestamp
targets -- a list of atoms as strings for the targets that should be saved, or nil if all available targets should be saved

Issues a request to the clipboard manager to store the clipboard data. On X11, this is a special program that works according to the freedesktop clipboard specification, available at freedesktop.org.