- str_repeat: documentation ( source)
- memory_get_usage: documentation ( source)
<?php
$x = 0;
$y = 0;
$x = memory_get_usage();
$s = str_repeat('c', 1200);
$y = memory_get_usage();
echo $y - $x, PHP_EOL;
$s1 = (string)$s;
$x = memory_get_usage();
echo $x - $y, PHP_EOL;