Q:

To know which package brought particular so library

I have /usr/lib32/libstdc++.so.6 library on my Ubuntu system. I would like to know which package brought it there. How to know that?

A:

Now that you know which package /usr/lib32/libstdc++.so.6 came from, you can find out which packages depend on lib32stdc++6 by running:
sudo apt-cache rdepends lib32stdc++6 
This will give you a list of package(s) that depend/installed lib32stdc++6 

A:

Please run dpkg -S /usr/lib32/libstdc++.so.6

