PHP is loosly typed so comparing an object with a boolean will result in this behavior.

try comparing with === or check the type of the returned object.

Ok, but then why does this work as expected (when a valid host, username, password, and db are supplied):

Reproduce code:
---------------
<?php
if (($db = mysqli_connect('localhost', 'user', 'password', 'db')) === false)
{
	echo 'equals false';
}
else
{
	echo 'does not equal false';
}
?>

Expected result:
----------------
does not equal false

Actual result:
--------------
does not equal false

Sorry, that code example should have been the following (same result happens):

<?php
if (($db = mysqli_connect('localhost', 'user', 'password', 'db')) == false)
{
	echo 'equals false';
}
else
{
	echo 'does not equal false';
}
?>

Just wondering if there is any update on this.  I really feel that this is a bug because there is a difference between the way the mysqli and simplexml objects work (between the mysqli_connect() and simplexml_load_string() functions) - since objects should work the same across the board.  Thanks.

If we have updates, we'll get back to you. No need to keep bugging us.

really not a bug.

simplexml returns an empty string in your case (no text content in <xml>), which is == false in PHP's loosely typed implementation. Just use === and it works as expected

Thanks - that makes sense with how simplexml works.  So others don't run into this, would it be possible add to the manual a warning about this on the simplexml_load_string and simplexml_load_file pages?  It's basically the same idea as the warning currently on http://www.php.net/strpos.  Thanks.