[Scons-users] difference between / purpose of the --implicit options

[TOM TANNER (BLOOMBERG/ LONDON)]

What exactly is the difference between --implicit-cache, --implicit-deps-changed and --implicit-deps-changed.

--implicit-deps-changed doesn't seem to do a lot, as I'd have thought that scons did this anyway.

And I can't see at all what --implicit-deps-unchanged does that --implicit-deps doesn't.

Thanks