<?php
/* Script showing that reset() takes its parameter by reference */
if (defined('HHVM_VERSION')) {
exit;
}
// adapted from http://php.net/manual/en/language.references.php#99644
$g_refcount_added = 0;
function refcount($var)
{
ob_start();
debug_zval_dump($var);
$dump = ob_get_clean();
$matches = array();
preg_match('/refcount\(([0-9]+)/', $dump, $matches);
$count = $matches[1];
global $g_refcount_added;
return $count - $g_refcount_added;
}
// configure our refcount function
$array = array('key' => 'value');
$refcount_expected = 1;
$refcount_actual = refcount($array); // 3 in PHP 7.0, 4 in other versions
$g_refcount_added = $refcount_actual - $refcount_expected;
unset($refcount_actual, $refcount_expected, $array);
// end of configure our refcount function
function print_refcounts($label, $orig_rc, $copy_rc = null)
{
if ($copy_rc === null) {
printf("%s : orig %d %s (%s)\n", $label, $orig_rc, " ", 'alone');
} else {
printf("%s : orig %d, copy %d (%s)\n", $label, $orig_rc, $copy_rc, $copy_rc > 1 ? 'sharing' : 'separated');
}
}
$orig = array('foo' => 'bar');
print_refcounts("initially ", refcount($orig));
$copy = $orig;
print_refcounts("after copy", refcount($orig), refcount($copy));
reset($copy); // if the argument is passed by reference, PHP separates $copy and $orig
print_refcounts("after call", refcount($orig), refcount($copy));
- Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.7
- initially : orig 1 (alone)
after copy : orig 2, copy 2 (sharing)
after call : orig 1, copy 0 (separated)
- Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.38, 7.0.0 - 7.0.33
- initially : orig 1 (alone)
after copy : orig 2, copy 2 (sharing)
after call : orig 1, copy 1 (separated)
preferences:
281.83 ms | 404 KiB | 452 Q