Zend Engine

Not to be confused withLaminasformerly known as Zend Framework.

Zend Engine

Original author(s)	Andi Gutmans,Zeev Suraski
Developer(s)	Zend Technologies,The PHP Development Team
Initial release	1999
Stable release	3.4 (PHP 7.4) 4.0 (PHP 8.0)
Repository	github.com/php/php-src
Written in	C
Type	Scripting engine
License	Zend Engine License(some parts are under thePHP License)
Website	www.zend.com

TheZend Engineis acompilerandruntime environmentfor thePHPscripting language and consists of the Zend Virtual Machine, which is composed of the Zend Compiler and the Zend Executor, that compiles and executes the PHP code.It was originally developed byAndi GutmansandZeev Suraskiwhile they were students at theTechnion – Israel Institute of Technology.They later founded a company calledZend TechnologiesinRamat Gan,Israel.The name Zend is a combination of their forenames, Zeev and Andi.

The first version of the Zend Engine appeared in 1999 in PHP version 4.It was written inCas a highly optimized modular back-end, which for the first time could be used in applications outside of PHP. The Zend Engine provides memory and resource management, and other standard services for the PHP language. Its performance, reliability andextensibilityplayed a significant role in PHP's increasing popularity.

This was followed byZend Engine 2at the heart ofPHP 5.

This was followed byZend Engine 3,originally codenamedphpng,which was developed forPHP 7and significantly improves performance.

The newest version isZend Engine 4,which was developed forPHP 8.

The source code for the Zend Engine has been freely available under theZend Engine License(although some parts are under thePHP License) since 1999,as part of the official releases from php.net, as well as the officialgitrepository or theGitHubmirror. Various volunteers contribute to the PHP/Zend Engine codebase.

Architecture

Zend Engine is used internally by PHP as a compiler and runtime engine. PHP Scripts are loaded into memory and compiled into Zendopcodes. These opcodes are executed and the HTML generated is sent to the client.

To implement a Web script interpreter requires three parts:

1. The interpreter part analyzes the input code, translates it, and executes it.
2. The functionality part implements the functionality of the language (its functions, etc.).
3. The interface part talks to the Web server, etc.

Zend takes part 1 completely and a bit of part 2; PHP takes parts 2 and 3.

Zend itself really forms only the language core, implementing PHP at its very basics with some predefined functions.

See also

• Free and open-source software portal

External links

• Official website
• "Zend Engine 2.0 Design"(PDF).Archived fromthe original(PDF)on 13 August 2011.
• Official git repository
• "Zend Engine Documentation".PHP development wiki.22 September 2017.