Project in a cvs, library in another

[Ababccc]

Hi all,
I am a complete cvs newbie.

I'm wondering what people usually do, in case there is a project on CVS 
which uses a C++ library which is in a completely separated CVS.

If the library gets changed (for its own purposes) the project might get 
screwed...

Do the people usually avoid using the CVS for the library? E.g. do they 
put a local non-cvs-copy of the library on the CVS of the project, and 
such library never gets updated?

Thanks
Ababccc