What language is the underlying structure of PHP built on?

When a user requests a PHP script in a web browser, the underlying PHP engine will transform these scripts into machine-executable instructions. This process is divided into two main steps:

Analysis: Initially, the PHP engine will analyze PHP scripts. This means that it will read and understand the syntax structure of the script, and convert it into an internal representation. During this stage, the PHP parser written in C language will perform lexical analysis, syntax analysis, and semantic analysis on the code to determine the structure and meaning of the script.

Compilation and execution: Once a PHP script is parsed, the PHP engine will use a compiler written in C language to convert the script into executable machine instructions. These instructions can be run directly on the computer. In addition, the PHP engine also contains many built-in functions and classes, which are also written in C language, providing various functions and features such as string manipulation, database access, and more.

In general, as the underlying language of PHP, C is responsible for parsing and compiling scripts, generating executable machine instructions, and providing various built-in functions and classes. This design allows PHP to be efficient, portable, and flexible, able to run on different operating systems and hardware platforms while providing stable and powerful functionality.