Knowing a little more about PHP

Hello dude! welcome back to ThyPHP, your PHP blog!. Today I will write about how to compile an extension of PHP on Unix and about an interesting tip found on PHP creator blog.

Yesterday I saw a post in Rasmus Lerdorf “toys page”. It was a nice post about MVC model… but the part that I surprise me…

Try to avoid using include_once and require_once if possible. You are much better off using a straight include or require call, because the *_once() calls are very slow under an opcode cache. Sometimes there is no way around using these calls, but recognize that each one costs you an extra open() syscall and hash look up.

This have some sense (he’s a main PHP code developer ), so I was figuring out how to solve this problem. The idea that I have was to have the C-like solution, use the “#ifdef”. Look in the example:

<?php
if ( ! defined(’SCRIPT_NAME’) ) {
define(’SCRIPT_NAME’, true);
//the code it self
}
?>

You can include the above PHP script. But after see this code again, it will be same thing that *_once…, because it will call open(), compile the code, and then execute, and avoid all execution because the first if will be false when a file included more than one time.

The only solution that I can figure out ( If you have other, please let me know) is to call the following function instead of call *_once:

<?php
function safe_include($script) {
static $included;
if ( ! isset($included[$script]) ) {
include $script;
$included[$script]=1;
}
}

?>

It is a very trivial and simple solution, but it may work. Of that the better solution is to code it well…

Compiling an extension for PHP

Some times when you are so lazy (such as me) for download and install PHP from it source (I love yum!) you may find that you need an extension. So the solution is to install PHP from the source?. The answer is not! You will need to compile somethings, but not install it…

1. Download the PHP source tarball.
2. Uncompress it (tar xfvz file-name.tar.gz)
3. Compile it.
   • cd php_dir
   • ./configure –with-dba=shared –with-sqlite=shared
   • make
4. Copy modules files to PHP extensions dir:
   • modules to copy = find . | grep module | grep so$
   • php extension dir = grep extension_dir /etc/php.ini
     
5. Back in PHP source code dir execute make distclean for clean the source code.
6. You can delete the the source folder now.
7. Create a file in /etc/php.d/module.ini (for each module) with the following content:
   extension=$module.so ; $module is your module name!
8. Restart your websever
9. It is done

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