Note:
Prior to working through the rest of this chapter, you should retrieve
clean, unmodified source trees of your favorite Web server. We're working with
Apache (available at
http://www.apache.org/)
and, of course, with PHP (available at
http://www.php.net/ - does
it need to be said?).
Make sure that you can compile a working PHP environment by
yourself! We won't go into this issue here, however, as you should
already have this most basic ability when studying this chapter.
Before we start discussing code issues, you should familiarize
yourself with the source tree to be able to quickly navigate
through PHP's files. This is a must-have ability to implement and
debug extensions.
The following table describes the contents of the major directories.
Discussing all the files included in the PHP package is beyond the
scope of this chapter. However, you should take a close look at the
following files:
php4/main/php.h, located in the main PHP directory.
This file contains most of PHP's macro and API definitions.
php4/Zend/zend.h, located in the main Zend directory.
This file contains most of Zend's macros and definitions.
php4/Zend/zend_API.h, also located in the Zend
directory, which defines Zend's API.
You should also follow some sub-inclusions from
these files; for example, the ones relating to the Zend executor,
the PHP initialization file support, and such. After reading these
files, take the time to navigate around the package a little to see
the interdependencies of all files and modules - how they relate to
each other and especially how they make use of each other. This
also helps you to adapt to the coding style in which PHP is
authored. To extend PHP, you should quickly adapt to this style.
Zend is built using certain conventions; to avoid breaking its
standards, you should follow the rules described in the following
sections.
