authentication problems

[Anon]

I'm trying to get the http authentication to work with a very simple little test program but I keep getting header errors. Here is the code:

<?
if (!$PHP_AUTH_USER || !$PHP_AUTH_PW)
{
// If empty, send header causing dialog box to appear
header('WWW-Authenticate: Basic realm="admin"');
header('HTTP/1.0 401 Unauthorized');
echo 'Authorization Required.';
exit;
}
else
{
if($PHP_AUTH_USER == "stf" && $PHP_AUTH_PW == "stf")
{
echo"in";
}
else
{
echo"out";
}
}
?>

Here is the errors messages its generating:

Warning: Undefined variable: PHP_AUTH_USER in d:\apache\htdocs\admin.php on line 2

Warning: Cannot add header information - headers already sent by (output started at d:\apache\htdocs\admin.php:2) in d:\apache\htdocs\admin.php on line 5

Warning: Cannot add header information - headers already sent by (output started at d:\apache\htdocs\admin.php:2) in d:\apache\htdocs\admin.php on line 6
Authorization Required.

I've been working on trying to get this to work for a long time but nothing seems to fix it. Any suggestions?

Thanks,
stf

[knight]

Sorry this is 3 hours late but try this code

<?php

if ( ( !isset( $PHP_AUTH_USER )) || (!isset($PHP_AUTH_PW))

|| ( $PHP_AUTH_USER != 'user' ) || ( $PHP_AUTH_PW != 'open' ) ) {

header( 'WWW-Authenticate: Basic realm="Private"' ); 
header( 'HTTP/1.0 401 Unauthorized' ); 
echo 'Authorization Required.'; 
exit; 

} else {

echo 'Success!'; 

}
?>

[Anon]

Worked perfectly, thanks Knight!

stf