What Happens Behind the Scenes When PHP Executes a Script?

PHP Script Execution Revealed

Programmers often speculate about the inner workings of PHP script execution, questioning the sequence of parsing and interpretation. This article delves into the intricacies of this process, providing a comprehensive explanation.

PHP has evolved over time and is now considered a compiled language. Contrary to popular belief, compilation doesn't necessarily imply converting source code into executable programs. Rather, it involves transforming code into an alternative representation.

Introducing the Zend Engine, PHP's secret weapon since version 4.0, this engine fragments PHP code processing into distinct phases. Initially, PHP source code is parsed, creating a binary representation called Zend opcodes. These opcodes, analogous to Java bytecodes, are essentially instruction sets stored in memory.

The Zend Engine's final phase executes these generated opcodes. By expertly handling opcodes, PHP's performance soars.

For further insights into PHP's compiler performance, refer to the article at: http://www.phpclasses.org/blog/post/117-PHP-compiler-performance.html

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