How to determine why a connection fails

Hi all;

I would like to add error handing which looks at why  DBI->connect()
call using DBD::Pg fails and handle it appropriately.  For example, if
the authentication fails, I would like to handle that one way, and the
db specified is not found, I would like to handle that a different
way.

After reviewing the docs, I don;t see a reasonable way to do this.
Can anyone point me in the right direction?

Best WIshes,
Chris Travers