fwrite(): supplied argument is not a valid stream resource - php

Question

I keep getting 3 errors when I use this code:
Warning: fopen() [function.fopen]: Filename cannot be empty
Warning: fwrite(): supplied argument is not a valid stream resource
Warning: fclose(): supplied argument is not a valid stream resource
I don't know what to do. I'm a php noob.
<?php
$random = rand(1, 9999999999);
$location = "saves/".$random;
while (file_exists($location)) {
$random = rand(1, 999999999999);
$location = "saves/".$random;
}
$content = "some text here";
$fp = fopen($location,"wb");
fwrite($fp,$content);
fclose($fp);
?>

Answer 1

As per your original question before your edit:
Since the file doesn't exist yet, your while condition won't work and that's why you're getting those error messages.
And since you're using a random number for the file, you will never know which file to open in the first place. Just remove the while loop.
Try this:
<?php
$random = rand(1, 999999999999);
$location = "saves/".$random;
$content = "some text here";
$fp = fopen($location,"wb");
fwrite($fp,$content);
fclose($fp);
?>

Answer 2

From the code you have, it looks like $location only exists inside the scope of the while loop. Try
<?php
$location = "";
while (file_exists($location)) {
$random = rand(1, 999999999999);
$location = "saves/".$random;
}
$content = "some text here";
$fp = fopen($location,"wb");
fwrite($fp,$content);
fclose($fp);
?>

Answer 3

first of all, you must set values to your $location variable or since the file is not yet created try this:
$random = rand(1, 999999999999);
$location = "saves/".$random;
$content = "some text here";
//if(file_exists($location)) $fp = fopen($location,"wb");
$fp = fopen($location, 'wb') or die('Cannot open file: '.$location); //implicitly creates file
fwrite($fp,$content);
fclose($fp);