Programming PHP, 2nd Edition

What You’ll Need

To develop a PHP extension, you’ll need a copy of the PHP source code and various software development tools, as discussed next.

The PHP Source

Fetch a copy of the current CVS version of the PHP code to ensure that you are using the most up-to-date version of the API. See http://cvs.php.net for instructions on how to obtain the CVS version of the code via anonymous CVS.

PHP comes with a skeleton extension framework generator called ext_skel; this little script is a lifesaver. You should spend some time studying the README.EXT_SKEL and README.SELF-CONTAINED-EXTENSIONS files that come with the PHP source code.

The PHP source code offers you dozens of example extensions to look at. Each subdirectory in the ext/ directory contains a PHP extension. Chances are that just about anything you need to implement will in some way resemble one of the existing examples, and you are strongly encouraged to steal/borrow as much existing code as possible (with proper attribution, of course).

Software Tools

To write an extension, you need to have working versions of these tools installed:

• bison

• flex

• m4

• autoconf

• automake

• libtool

• An ANSI-compliant compiler such as gcc

• make

• sed, awk, and Perl are also used optionally here and there

These are all standard tools available free on the Internet (see http://www.gnu.org for most of them). If you are running a Linux distribution or any of the BSD operating systems, follow your distribution’s mechanism for installing new packages.

On Windows, things are a little ...