WordPress at a glance
function is not described

SplFixedArray::key() public WP 1.0

Return current array index

{} It's a method of the class: SplFixedArray{}

No Hooks.

Return

Int. The current array index.

Usage

$SplFixedArray = new SplFixedArray();
$SplFixedArray->key();

Code of SplFixedArray::key() WP 5.7

<?php
public function key()
{
    return key($this->internalArray);
}