requiring a password to connect

Hi all,

I am using postgresql in conjunction with php. The following code works to
establish a database connection:

$db = pgConnect("dbname=mydb user=myuser");

I would prefer it if this would fail to connect. Is there a command line
switch I can use to start the postmaster that will require a password to be
passed in the connection string? Or do I need to recompile postgresql with
a particular option to achieve the desired behavior? I have experienced the
above on 6.5.3, 7.0.2 and 7.1.2.

Thank you very much for your time,
~c