(PHP 4, PHP 5, PHP 7) Checks if the class has been defined

(PHP 4, PHP 5, PHP 7) Return info about a group by name

(PHP 5 >= 5.5.5, PHP 7, PECL ZendOpcache > 7.0.2) Get status information about the cache

(PECL trader >= 0.2.0) Vector Trigonometric Cos

(PHP 4, PECL pdflib >= 1.0.0) Set miter limit

(PECL proctitle >= 0.1.0) Set the process title

(PHP 5 >= 5.3.0, PHP 7, PECL intl >= 1.0.0) Set a text attribute

(PHP 5 >= 5.1.0, PHP 7) Gets the behavior flags.

(PHP 5 >= 5.3.0, PHP 7, PECL intl >= 1.0.0) Set formatter pattern

(PHP >= 5.3.0, PECL phar >= 1.0.0) Returns the Phar file entry flags