When you export to SWF does entire library go?

i have a quick question:

once u make a SWF, do all of your library items go into the SWF as well?

the real question is this:

will having alot of extra items in my FLA library make the SWF bigger in filesize?

(or will it only grab whats used into the SWF?)

hope that’s clear enough to understand

thanx

z