Loop stopped at 65536 - php

Question

I make a loop until 500000 and it stop at 65536, dies this php limit or system limit? Anyway to avoid it?
Btw, it's just an ordinary for loop.
for($i=0; $i<500000; $i++){}
real code, I care about the load, but my concern is not that one.
class ECStun{
var $sp = 1;
var $d = 5;
var $url = 'http://example.com/';
var $html = '';
var $invalid = '404';
var $data = array();
var $db = false; // db connection
var $dbhost = 'localhost';
var $dbuser = 'root';
var $dbpass = '';
var $dbname = 'scrape';
var $tbname = 'ecstun'; // this table will be created automatically by the script.
var $proxies = array(
);
var $startat = 0;
function init(){
$this->initDB();
$this->startat = microtime(true);
$x = rand(0, count($this->proxies)-1);
print('start scraping using proxy : '.$this->proxies[$x]."\n");
for($i = $this->sp; $i <= $this->d; $i++){
$url = $this->url.'ES'.$i;
if(!$this->isSaved($url)){ // skip is already saved to DB
$link = curl_init();
if(count($this->proxies) > 0){
curl_setopt($link, CURLOPT_PROXY, $this->proxies[$x]);
}
curl_setopt($link, CURLOPT_URL, $url);
curl_setopt($link, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.52 Safari/537.17)');
curl_setopt($link, CURLOPT_RETURNTRANSFER, true);
curl_setopt($link, CURLOPT_FOLLOWLOCATION, true);
$this->html = curl_exec($link);
$code = curl_getinfo($link, CURLINFO_HTTP_CODE);
curl_close($link);
if($code == 200 || $code == 301){
$this->parse($url);
}else{
/*
** this block of script will make sure if IP got banned then delete the banned ip
** and then check if there is another remaining IPs we can use
** if no more IPs in $proxies then exit the script with information of latest ES
*/
//unset($this->proxies[$x]);
array_splice($this->proxies, $x, 1);
if(count($this->proxies) > 0){
$this->sp = $i; // if banned then set starting point to the latest ES to try again using different ip
$this->init();
}else{
exit('LAST ES: ES'.$i);
}
}
}
}
//$this->initDB();
}
}
$ecs = new ECStun;
if(isset($_GET['verify_proxy'])){ // browser only
$ecs->verifyProxy();
}else{
$ecs->init();
}

Answer 1

65535 is a magical number. From wikipedia:
65535 occurs frequently in the field of computing because it is the
highest number which can be represented by an unsigned 16-bit binary
number.
Try this:
var_dump(PHP_INT_MAX);
It should be the 65535 to confirm your error. Try upgrading to 32 bit or more.