Reserved Names

PHP shares several namespaces with the users, and has reserved some names for its own usage.

  • Namespaces : the global namespace, also known as \ is reserved for PHP.

  • Keywords : fn, finally, insteadof, null, void, …

  • classes, constants, functions, interfaces

  • variables : $GLOBALS, $_GET,…

<?php

// function void() would not compile
function theVoid() : bool { }

?>

Documentation

See also Predefined Variables