[Mediawiki-l] Any reason why superglobals are null in localsettings.php?

[Brian Carpenter]

Any brainstorms why the following would produce null output when
placed near the 'bottom' in Localsettings.php?

$sso_ID = $_SERVER['HTTP_SSO_ID'];
error_log( SSO ID=".$_SERVER['HTTP_SSO_ID']."\n",3, 'c:\wiki\errorlog.txt' );
error_log( SSO ID=".$sso_ID."\n",3, 'c:\wiki\errorlog.txt' );

HTTP_SSO_ID is can be output by visiting page  test.php, which contains:

<?php
$sso_ID  = $_SERVER['HTTP_SSO_ID'];
print "The SSO ID is $sso_ID<br />";
?>

Thanks,
Brian