[!--quoteo(post=365022:date=Apr 15 2006, 05:16 AM:name=Barand)--][div class=\'quotetop\']QUOTE(Barand @ Apr 15 2006, 05:16 AM) [snapback]365022[/snapback][/div][div class=\'quotemain\'][!--quotec--]1 ) Both parts of an AND expression are supposed to be boolean expressions evaluating to true or false. die() returns void. [/quote]Well, wouldn't the same be true about an OR expression? Both parts are supposed to be boolean expressions. However, in the php manual, especially with the mysql functions, there are lots of examples like this one taken from [a href=\"http://us3.php.net/manual/en/function.mysql-fetch-array.php\" target=\"_blank\"]http://us3.php.net/manual/en/function.mysql-fetch-array.php[/a] : <?php mysql_connect("localhost", "mysql_user", "mysql_password") or die("Could not connect: " . mysql_error()); ...... [!--quoteo(post=365022:date=Apr 15 2006, 05:16 AM:name=Barand)--][div class=\'quotetop\']QUOTE(Barand @ Apr 15 2006, 05:16 AM) [snapback]365022[/snapback][/div][div class=\'quotemain\'][!--quotec--]2 ) Both parts should be evaluated to see if the whole expression gives true or false, therefore one would expect the die() to be executed in all cases. [/quote]I don't think this is true because according to the manual AND and OR epressions are short-circuited. Meaning that, in an AND expression, if the first part is false, php won't evaluate the second part because, even if it did, the whole expression is already false. The same is true with the OR expression. If the first part is true, php won't evaluate the second part, because the whole expression is already true. [!--quoteo(post=365022:date=Apr 15 2006, 05:16 AM:name=Barand)--][div class=\'quotetop\']QUOTE(Barand @ Apr 15 2006, 05:16 AM) [snapback]365022[/snapback][/div][div class=\'quotemain\'][!--quotec--]I can only assume that this works only because of current deficiency in the PHP processor and shouldn't be relied upon, apart from being virtually unreadable to anyone having to maintain your code. [/quote]I don't think it's a deficiency as php was, again according to info in the manual, designed to have the short-circuit or lazy evaluation feature. I do agree that it is pretty unreadable though. A programmer that's not used to seeing code written that way would probably take long to figure out what's going on.