spl_classes
Note that the contents (properties) of the object are NOT hashed by the function, merely its internal handle and handler table pointer. This is sufficient to guarantee that any two objects simultaneously co-residing in memory will have different hashes. Uniqueness is not guaranteed between objects that did not reside in memory simultaneously, for example:
var_dump(spl_object_hash(new stdClass()), spl_object_hash(new stdClass()));
Running this alone will usually generate the same hashes, since PHP reuses the internal handle for the first stdClass after it has been dereferenced and destroyed when it creates the second stdClass.
spl_object_hash
(PHP 5 >= 5.2.0)
spl_object_hash — Return hash id for given object
Description
string spl_object_hash
( object
$obj
)This function returns a unique identifier for the object. This id can be used as a hash key for storing objects or for identifying an object.
Parameters
-
object -
Any object.
Return Values
A string that is unique for each currently existing object and is always the same for each object.
Examples
Example #1 A spl_object_hash() example
<?php
$id = spl_object_hash($object);
$storage[$id] = $object;
?>
Notes
Note:
When an object is destroyed, its hash may be reused for other objects.
add a note
User Contributed Notes
spl_object_hash - [2 notes]
planetbeing ¶
5 years ago
Rafael M. Salvioni ¶
4 years ago
The follow function is a implementation of the PHP´s function spl_object_hash(), unavailable in versions less 5.2.0.
But, the algorithm of this function is different of the original PHP´s function.
(Sorry... my english is very bad...)
<?php
if (!function_exists('spl_object_hash')) {
/**
* Returns the hash of the unique identifier for the object.
*
* @param object $object Object
* @author Rafael M. Salvioni
* @return string
*/
function spl_object_hash($object)
{
if (is_object($object)) {
ob_start(); var_dump($object); $dump = ob_get_contents(); ob_end_clean();
if (preg_match('/^object\(([a-z0-9_]+)\)\#(\d)+/i', $dump, $match)) {
return md5($match[1] . $match[2]);
}
}
trigger_error(__FUNCTION__ . "() expects parameter 1 to be object", E_USER_WARNING);
return null;
}
}
?>