<?php
function test()
{
	$link2 = mysql_connect('localhost', 'phpde', 'phpde');
	var_dump($link2);	
	echo mysql_error();
	mysql_select_db('ratbytes', $link2);
	echo mysql_error();
	$result = mysql_query('SELECT * FROM rb_user', $link2);
	echo mysql_error();	
	mysql_fetch_array($result);
	echo mysql_error();	
	mysql_close($link2);
	echo mysql_error();	
}

$link = mysql_connect('localhost', 'phpde', 'phpde');
var_dump($link);
echo mysql_error();
mysql_select_db('ratbytes', $link);
echo mysql_error();

test();

$result = mysql_query('SELECT * FROM rb_user', $link);
echo mysql_error();
mysql_fetch_array($result);
echo mysql_error();
mysql_close($link);
echo mysql_error();
?> 

produced following output:

resource(1) of type (mysql link)
resource(1) of type (mysql link) 
Warning: mysql_query(): 1 is not a valid MySQL-Link resource in ....test.php on line 25
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in ....test.php on line 27
Warning: mysql_close(): 1 is not a valid MySQL-Link resource in ....test.php on line 29

... works fine if no link_identifier is specified (mysql_close)

<?php
$link = mysql_connect('localhost', 'phpde', 'phpde');
var_dump($link);
echo mysql_error();
mysql_select_db('ratbytes', $link);
echo mysql_error();

// start inline
$link2 = mysql_connect('localhost', 'phpde', 'phpde');
var_dump($link2);	
echo mysql_error();
mysql_select_db('ratbytes', $link2);
echo mysql_error();
$result = mysql_query('SELECT * FROM rb_user', $link2);
echo mysql_error();	
mysql_fetch_array($result);
echo mysql_error();	
mysql_close($link2);
echo mysql_error();	
// end inline

$result = mysql_query('SELECT * FROM rb_user', $link);
echo mysql_error();
mysql_fetch_array($result);
echo mysql_error();
mysql_close($link);
echo mysql_error();
?> 

produced following output:
resource(1) of type (mysql link)
resource(1) of type (mysql link)