How to find package name for files

["Timothy Wu" <2huggie@gmail.com>]

Hi,

I am trying to upgrade libstdc++.so.6.0.8 to a newer version in the /usr/lib directory. I used aptitude to install libstdc++6-dev package. But the /usr/lib so file is still not updated. I suspect that's not the package for it. 

Given an existing file, Is there any method to find out which package the file comes from? If I can find out which package the file is from, maybe I can guess the name of the newer package.

Timothy