cvs export -P?

[Edd]

Hi there,
I wish to know how to export from cvs and prune empty directories. I know
a co can be done and pruned by:

cvs co -rSOMETAG -P module

but:

cvs export -rSOMETAG -P module

only show me the usage help even though I have read in may places that -P
does infact apply with export too.

Thanks!