Checking For Names At Different Times

<?php


class stdClass {}
// Checked at execution time

interface Iterator {}
// Checked at execution time

function mb_substr() {}
// Checked at compile time

PHP lint detects early to avoid redeclared functions, based on the local PHP executable.

php -l => Cannot redeclare mb_substr().

That detection doesn’t apply to CITE until execution.

php => Cannot declare class stdClass

because the name is already in use``. This is a difference in processing similar information, which may cause late surprises.

See Also

• When to check for name [Try me]

PHP Features

• class

• function

• cite

Last updated: 14 July 2026