<?php
class Singleton
{
/**
* @var Singleton The reference to *Singleton* instance of this class
*/
protected static $instance;
/**
* Returns the *Singleton* instance of this class.
*
* @return Singleton The *Singleton* instance.
*/
public static function getInstance()
{
if (null === static::$instance) {
static::$instance = new static();
}
return static::$instance;
}
/**
* Protected constructor to prevent creating a new instance of the
* *Singleton* via the `new` operator from outside of this class.
*/
protected function __construct()
{
}
/**
* Private clone method to prevent cloning of the instance of the
* *Singleton* instance.
*
* @return void
*/
private function __clone()
{
}
/**
* Private unserialize method to prevent unserializing of the *Singleton*
* instance.
*
* @return void
*/
private function __wakeup()
{
}
}
class SingletonChild extends Singleton
{
}
$obj = Singleton::getInstance();
var_dump($obj === Singleton::getInstance()); // bool(true)
$anotherObj = SingletonChild::getInstance();
var_dump($anotherObj === Singleton::getInstance()); // bool(false)
var_dump($anotherObj === SingletonChild::getInstance()); // bool(true)
Warning: The magic method Singleton::__wakeup() must have public visibility in /in/YSPL3 on line 48
bool(true)
bool(true)
bool(true)
Output for 8.3.5
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
Warning: The magic method Singleton::__wakeup() must have public visibility in /in/YSPL3 on line 48
bool(true)
bool(true)
bool(true)
Parse error: syntax error, unexpected T_STATIC in /in/YSPL3 on line 17
Process exited with code 255.
Output for 5.0.0 - 5.0.5
Parse error: parse error, unexpected T_STATIC in /in/YSPL3 on line 17
Process exited with code 255.
Output for 4.4.2 - 4.4.9
Parse error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /in/YSPL3 on line 8
Process exited with code 255.
Parse error: parse error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /in/YSPL3 on line 8
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error, expecting `T_OLD_FUNCTION' or `T_FUNCTION' or `T_VAR' or `'}'' in /in/YSPL3 on line 8
Process exited with code 255.