multiple formats on clipboard

[Kasper Peeters <kasper peeters aei mpg de>]

Hi,

I have an application in which output can be selected with the mouse,
after which it should be available on the clipboard. However, the
output can be put on the clipboard in two different formats: an
"external" one, useful only when pasting into other applications, and
an "internal" one, useful only when pasting back into the TextViews of
the program itself (or an arbitrary other running copy of it).

I understand how to use "Clipboard::set" to offer the selection in two
different formats, say "X" and "Y". How now do I instruct the TextView
widgets in my program to request the clipboard content in format "X",
while making standard middle mouse paste actions in other programs use
format "Y"?

Best,
Kasper