Octal Integer

Integers can be specified in octal, or base 8, notation. Octal integer syntax starts with 0o, zero-o, and only contains digits from 0 to 7.

Initially, octal integers were formatted by simply starting with a initial 0. This features is still available, yet should be replaced with the less confusing syntax with 0o.

<?php

    // 12
    $octal = 0O14;
    $octal = 014;

?>

Documentation

See also PHP 8.1: Explicit Octal numeral notation.

Related : integer, Binary Integer, Hexadecimal Integer, Leading Zero Means Octal