A function to be called when the results of gtk_clipboard_request_rich_text() are received, or when the request fails.
the #GtkClipboard
The format of the rich text
the rich text received, as a UTF-8 encoded string, or %NULL if retrieving the data failed.
Length of the text.
A function to be called when the results of gtk_clipboard_request_rich_text() are received, or when the request fails.