Special Types函数详解

<?php
	$conn = ftp_connect("127.0.0.1") or die("Could not connect");
	echo get_resource_type($conn);
?>

<?php
	$conn= ftp_connect("127.0.0.1") or die("could not connect");
	echo $conn;
?>

<?php
	$handle = fopen("tpoint.txt", "r");
	var_dump($handle);
	echo "<br>";
	$conn= ftp_connect("127.0.0.1") or die("could not connect");
	var_dump($conn);
?>

<?php
$empty=null;
var_dump($empty);
?>

<?php
    	$a1 = " ";
   	var_dump($a1);
    	echo "<br />";
    	$a2 = null;
    	var_dump($a2);
?>

<?php
	$x = NULL;
	var_dump($x);
	echo "<br>";
	$y = "Hello Learnfk!";
	$y = NULL;
	var_dump($y);
?>