From the preface of the manual:
PHP is an HTML-embedded scripting language. Much of
its syntax is borrowed from C, Java and Perl with a couple of unique
PHP-specific features thrown in. The goal of the language is to
allow web developers to write dynamically generated pages quickly.
A nice introduction to PHP by Stig S犚her Bakken can be found
here on the Zend
website. Also, much of the
PHP Conference Material is freely available.
2. What does PHP stand for?
PHP stands for PHP: Hypertext Preprocessor.
This confuses many people because the first word of the acronym is
the acronym. This type of acronym is called a recursive acronym.
The curious can visit
Free On-Line Dictionary of Computing
for more information on recursive acronyms.
3. What is the relation between the versions?
PHP/FI 2.0 is an early and no longer supported version of PHP. PHP 3
is the successor to PHP/FI 2.0 and is a lot nicer. PHP 4 is the current
generation of PHP, which uses the Zend
engine under the hood. PHP 5 uses Zend engine 2 which, among other
things, offers many additional OOP
features. PHP 5 is experimental.
4. Can I run several versions of PHP at the same time?
Yes. See the INSTALL file that is included
in the PHP 4 source distribution. Also, read the related
5. What are the differences between PHP 3 and PHP 4?
There are a couple of articles
written on this by the authors of PHP 4. Here's a list of some of
the more important new features:
Extended API module
Generalized build process under UNIX
Generic web server interface that also supports
multi-threaded web servers
Improved syntax highlighter
Native HTTP session support
Output buffering support
More powerful configuration system
Please see the What's new in
PHP 4 overview
for a detailed explanation of these
features and more. If you're migrating from PHP 3 to PHP 4,
also read the related appendix
I think I found a bug! Who should I tell?
You should go to the PHP Bug Database and make sure the bug
isn't a known bug. If you don't see it in the database, use
the reporting form to report the bug. It is important to use
the bug database instead of just sending an email to one of the
mailing lists because the bug will have a tracking number assigned
and it will then be possible for you to go back later and check
on the status of the bug. The bug database can be found at