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PHP programming language

The computer language PHP (originally "Personal Home Page", but now a recursive acronym for "PHP Hypertext Preprocessor") is a widely used open-source programming language used primarily for server-side applications, to develop dynamic web content such as the Wikipedia software. It can be seen as an open source alternative to Microsoft's Active Server Pages (ASP) system and to the similar CGI/Perl system.

Its ease of use and similarity with the most common structured programming languages, most notably C, Java and Perl, allows most experienced programmers to start developing complex applications with a minimal learning curve. It also enables experienced developers to get involved with dynamic web content applications without having to learn a whole new set of functions and practices.

One of the more attractive parts of PHP is that it is not only a scripting language. Because it has been designed from the start to be modular, the PHP core system has been used to develop desktop applications that are close to the same performance as traditional C++ compiled applications, and it can be used from the command line just like Perl or Python.

PHP allows, among other things, easy interaction with a very large number of relational database systems (Oracle[?], DB2, MySQL, PostgreSQL, etc.), while maintaining a simple and straightforward syntax. PHP runs on every major operating system, including Unix, Linux, Windows, and Mac OS X and can interact with all major web servers. The PHP website (php.net) has some of the best documentation pages of any project, and has lots of help with setting up PHP on obscure operating systems and web-servers. The Linux, Apache, MySql, PHP (LAMP) architecture has become very popular in the industry for deploying reliable, scalable and secure web applications.

PHP is the result of the collective efforts of many contributors. It is licensed under a BSD-style license, the PHP license (http://www.php.net/license/3_0.txt).

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PHP's Libraries

PHP, unlike ASP and Perl, has some of the largest free and open-source libaries included with the core build. PHP is a fundamentally internet-aware system and as such there are modules built in for accessing FTP servers, all manners of database servers, LDAP servers and much more. What's more the most used functions such as printf(), str_replace(), preg_match() from C are all available from PHP.

PHP has a wide variety of extensions such as support for the Windows API, Process Management on Linux, cURL support, ZIP and GZip support. Some of the more unique features are PDF generation, Shockwave Flash generation (on the fly), integration with IRC and much more besides.

History

PHP was originally designed as a wrapper around Perl by Rasmus Lerdorf in 1994 to display his resume information, and collect some data, such as how many hits it was generating. Others first used "Personal Home Page Tools" in 1995, which Lerdorf had combined with his own Form Interpreter to create PHP/FI. Zeev Suraski and Andi Gutmans rewrote the parser in 1997, forming the basis of PHP 3. They also changed the name to its current recursive form. After months in beta, the development team officially released PHP/FI 2 in November 1997. Public testing of PHP 3 began immediately and the official launch came in June 1998. Suraski and Gutmans started a new rewrite of PHP's core, producing the Zend engine in 1999. In May 2000, PHP 4 powered by the Zend Engine was released. Development continues toward PHP 5 with Zend Engine 2.

Popularity of PHP

PHP is one of the most popular server-side scripting systems on the Web. It's been widely adopted since the release of version 4, which was the first version powered by the powerful Zend Engine from Zend Technologies[?].

According to Netcraft's (http://www.netcraft.com/info) April 2002 survey, PHP is now the most-deployed server-side scripting language, running on around 9 million of the 37 million sites in their survey. This is confirmed by PHP.net's own figures (http://www.php.net/usage.php), which show PHP usage measured on a per-domain basis growing at around 5% per month.

PHP is not, however, the most commonly used tool if measurements are made on a per-page basis. Another estimate in March 2002, based on searching for Web pages by their suffix, places PHP in second place at 30% of measured pages, behind 48% using Microsoft's ASP, but also shows PHP growing rapidly in market share. However, this method is notoriously inaccurate for measuring PHP popularity as some PHP systems dispense with the file names, using only directories.

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