wait_for_retrieval(clipboard, (void **) &selection_data); return selection_data;
wait_for_retrieval(clipboard, &context); return NS_STATIC_CAST(GtkSelectionData *, context.data);
wait_for_contents(GtkClipboard *clipboard, GdkAtom target){    GtkSelectionData *selection_data = NULL;    gtk_clipboard_request_contents(clipboard, target,                                   clipboard_contents_received,                                   &selection_data);    wait_for_retrieval(clipboard, (void **) &selection_data);    return selection_data;}