Listing 1. Sammple Library Coding
common.php:
<?php
//connect to postgres database
$conn=pg_pconnect("user=tim dbname=db_example");
//see if our connection was successful
if (!$conn) {
	//connection failed-exit the page with an
        //error
	//you could also try to proceed without the 
	//database-it's up to you
	echo pg_errormessage($conn);
	exit;
}
//now let's set up a common site header
function site_header ($title) {
	return '<HTML>
	<HEAD>
	<TITLE>'.$title.'</TITLE>
	</HEAD>
	<BODY>';
}
//common HTML to be output at the end of the page
function site_footer () {
	return '</BODY></HTML>';
}
//a simple wrapper to reduce the code needed
//for each postgres query
function query($sql) {
	global $conn;
	return pg_exec($conn,$sql);
}
//have PHP4 set up/restore your session state
//automatically on every page
session_start();
?>