PHP is a server-side scripting language designed for web development but also used as a general-purpose programming language. As of January 2013, PHP was installed on more than 240 million websites (39% of those sampled) and 2.1 million web servers. Originally created by Rasmus Lerdorf in 1994, the reference implementation of PHP (powered by the Zend Engine) is now produced by The PHP Group. While PHP originally stood for Personal Home Page, it now stands for PHP: Hypertext Preprocessor, which is a recursive acronym.

When developing compilers and interpreters, their source code and its testing procedure are demanded to comply with especially strict quality and reliability requirements. However, there are still some suspicious fragments found in the PHP interpreter's source code.

In this article, we are going to discuss the results of the check of the PHP interpreter by PVS-Studio 5.18.