Better yet:

package ECClib;

my $dbh;

sub get_dbh {
  $dbh ||= db_connect( $dbuser, $dbpasswd, $dbserver );
}
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And:

use ECClib;

{
  my $dbh = ECClib->get_dbh;
  ...;
}

{
  my $dbh = ECClib->get_dbh;  # gets the same instance!
  ...;
}
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If you're using Perl 5.10+:

package ECClib;
use v5.10;

sub get_dbh {
  state $dbh = db_connect( $dbuser, $dbpasswd, $dbserver );
}
[download]