How to create a sub branch for an existing branch in CVS?

I created a branch for开发者_Python百科 my sources. I want to create a sub branch for the existing branch. Is it possible using CVS ?

Just check out the "parent" branch, then create the "sub-branch".

However, please note that CVS itself is not really aware of "branch parenthood". Branches are always attached to revisions, not to other branches. Thus this can only be tracked (in revision graphs and such) for files that actually had revisions on the "parent" branch. Otherwise both parent and child will simply stem from the same branchpoint revision.