getting the correct sub

hi

if i have a bunch of require's happening and all those
required files happen to use some of the same named subs.
how do i make sure my program uses exactly the one i want?

in mod_perl it seemd straightforward but what do i do in a
normal perl-program?

mod_perl:
my $dbh = Apache::somewhere::db::connection::connection_postgres::get_sub();


../allan