package CitySearcher;

use strict;

...
use Tree::Trie;
use threads::shared;
use APR::OS;

my $TRIE :shared;
my $TRIE_LOCK :shared = {};

sub handler {
	my $r = shift;
	$r->content_type('text/html');
	
	...
	
	my $request = new CGI;
	my $tid = APR::OS::current_thread_id();
	lock($TRIE_LOCK);
	if(!defined($TRIE)) {
		print stream "$$-$tid: creating trie\n";
		my $trie = new Tree::Trie;
		...
		#populate $trie
		...		
		$TRIE = shared_clone($trie);
	}
	
	print stream "$$-$tid: returning trie\n";
	
	...
	#use trie
	...

	return Apache2::Const::OK;
}

1;

##</code><code>##

10320-3056253808: creating trie
10320-3056253808: returning trie
10320-3064646512: returning trie
10320-3056253808: returning trie
10320-3064646512: returning trie
10320-3064646512: returning trie
10320-3056253808: returning trie
10320-3064646512: returning trie
10320-3056253808: returning trie
10320-3064646512: returning trie
10320-3064646512: returning trie
10320-3022682992: creating trie
10320-3022682992: returning trie
10320-3047861104: creating trie
10320-3047861104: returning trie
10320-3056253808: returning trie
10320-3056253808: returning trie
10320-3022682992: returning trie
10320-3064646512: returning trie
10320-3031075696: creating trie
10320-3031075696: returning trie
10320-3064646512: returning trie
10320-3022682992: returning trie
10320-3056253808: returning trie
10320-3056253808: returning trie
10320-3039468400: creating trie
10320-3039468400: returning trie
10320-3022682992: returning trie
10320-3064646512: returning trie
10320-3056253808: returning trie