Pass variable to pcntl_fork child in PHP

Question

I've tried the following code but the $call variable is not available in the pcntl_fork child. Searching the web, I've found posts that claim that all variables defined before pcntl_fork are copied to the child. I've also found posts that claim that no variables are passed/copied to the child. So, which of them is true and how should I correct my code to make it work?

 $call = str_replace('@@', '&', $_GET['call']);

 if ($pid = pcntl_fork())
 {
     $previousCalls=file("calls.txt", FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
     if (!in_array($call, $previousCalls))
     {
         file_put_contents("calls.txt", $call."\n", FILE_APPEND);
     }
 }
 else
 {
     function displayUrl($url)
     {
         $ch = curl_init($url);
         curl_setopt ( $ch, CURLOPT_HEADER, 1);
         curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
         $curlResult = curl_exec($ch);
         curl_close($ch);
         list($headers,$content) = explode("\r\n\r\n",$curlResult,2);
         foreach (explode("\r\n",$headers) as $hdr)
         {
             if ($hdr != 'Transfer-Encoding: chunked')
             {
                 header($hdr);
             }
         }
         echo $content;
     }
     displayUrl($call);
 }

Answer 1

Child process should has the same environment as the parent process. I
don't see any thing wrong with your code.
I assume that you are using php to handle http request for the using of
$_GET , but I think it is wrong to use multi process in PHP in the HTTP
SERVER environment