2 Questions: Static variables and the nature of the online manual

Hello, I got this e-mail address from the ŒAdd note¹ page within the php.net website. I was going to post something that was a question and I realised I was in the wrong place :) I have 2 basic questions and I¹m sorry if they may seem too basic. I¹m a bit new to php. The first question has to do with the static variables. I understand how this works from the examples, but there is something that I cannot seem to find clearly stated anywhere on that page. The example: <?php function Test() { static $a = 0; echo $a; $a++; } ?> Of course works (I¹ve tested it on my server), but it is still obscure to me, according to general programming principles, since I¹m still assigning zero (0) to $a on each call to the Test function. How does this exactly work when the static word is found? Is there and index that keeps track of each call to the function ignoring any assignment in subsequent calls to the function? Why doens¹t this work when you assign an expression result to the variable? The second question has to do with the online manual. I¹ve found several things on that manual specified in comments and not in the actual manual part of it. What is the nature of the manual? Contributions from voluteers? Is there any official manual I can buy that documents everything about the language from the source? Or any official company that maintains the language and that possibly offers support as well? Many thanks in advance for your time.