Fastest way to check database's existence

I want to code a Perl function (part of a Perl library) for determining the
existence of a particular database (in a given host/port).

One way would be to just attempt making a connection to it, trapping any
errors upon failure (with eval), or discarding the connection upon success.

This approach has the added benefit of also checking the accessibility of
the database to the user running the code, but for this application this
added benefit is not necessary. Checking existence is all that matters.

Is there an even faster way to check for a database's existence that does
not require establishing a connection?

(Maybe this question would be more suitable for the pgsql-performance list?)

TIA!

~kynn