???

drag0n

Ive been reading this book and I got to the chapter about writing and reading text files, i understood the writing script, but this one confused me:

<html>
<head>
  <title>Bob's Auto Parts - Customer Orders</title>
</head>
<body>
<h1>Bob's Auto Parts</h1>
<h2>Customer Orders</h2>
<?

   $fp = fopen("../../orders/orders.txt", "r");

   flock($fp, 1);   

   if (!$fp)
   {
     echo "<p><strong>No orders pending."
         ."Please try again later.</strong></p></body></html>";
     exit;

   }

   while (!feof($fp))
   {
      $order= fgets($fp, 100);
      echo $order."<br>";
   }
   flock($fp, 3);   

/*
   echo "Final position of the file pointer is ".(ftell($fp));
   echo "<br>";
   rewind($fp);
   echo "After rewind, the position is ".(ftell($fp));
   echo "<br>";
*/
   fclose($fp);
?>
</body>
</html>

What does the while(!feof($fp)) do?
Why do you need it? I thought while loops needed conditions in them right? Is flock($fp, 30); a php function? What does it do?
Also, what does the ! infront of FEOF mean? I see that in front of the error reporting too.
Sorry for asking so many questions, but Imj really excited in learning PHP, I just got the book tonight lol.

onlinegs

The Exclamation pont (!) switches a statment from false to true, or from true to false. This is used so that if something reports false, can switch it to true and execute the error condition loop.

http://www.php.net/manual/en/function.feof.php - that link contains information on the function feof()

and

http://www.php.net/manual/en/function.flock.php - that link contains information on the function flock()

drag0n

why did they need a (!) infront of the FEOF? Why did they have to make that true or false? Thats just to read till end of file, right? Does that (!) switch it to true? or false? Thanks for giving me the links, now Ive passed this chapter =)

Floodboy

FEOF means File End Of File.

Is a bucle that says, while the pointer isn't at the end of a file:

while (!feof($fp))

and flock($fp, 1); lock the file for reading (I guess, coz I can't remember :p ) so yo when you open the file and you have flock 1 will prevent php for reading and flock 3 will unlock this file