Even I have never been using this function, just a simple example in order to explain it;
./myClass.php
<?php
class myClass {
public function __construct() {
echo "myClass init'ed successfuly!!!";
}
}
?>
./index.php
<?php
// we've writen this code where we need
function __autoload($classname) {
$filename = "./". $classname .".php";
include_once($filename);
}
// we've called a class ***
$obj = new myClass();
?>
*** At this line, our "./myClass.php" will be included! This is the magic that we're wondering... And you get this result "myClass init'ed successfuly!!!".
So, if you call a class that named as myClass then a file will be included myClass.php if it exists (if not you get an include error normally). If you call Foo, Foo.php will be included, and so on...
And you don't need some code like this anymore;
<?php
include_once("./myClass.php");
include_once("./myFoo.php");
include_once("./myBar.php");
$obj = new myClass();
$foo = new Foo();
$bar = new Bar();
?>
Your class files will be included "automatically" when you call (init) them without these functions: "include, include_once, require, require_once".
__autoload
(PHP 5, PHP 7)
__autoload — Attempt to load undefined class
Warnung
Dieses Feature ist seit PHP 7.2.0 als DEPRECATED (veraltet) markiert. Sich auf dieses Feature zu verlassen ist in keiner Weise empfehlenswert.
Beschreibung
__autoload
( string
$class
) : voidYou can define this function to enable classes autoloading.
Parameter-Liste
-
class -
Name of the class to load
Rückgabewerte
Es wird kein Wert zurückgegeben.
add a note
User Contributed Notes 11 notes
qeremy ¶
7 years ago
ohcc at 163 dot com ¶
5 years ago
It is highly recommended not to use the __autoload() function any more. Now the spl_autoload_register() function is what you should consider.Sorry for the mistake in line 6 of my previous note. And below is the corrected PHP code.
<?php
if(!function_exists('classAutoLoader')){
function classAutoLoader($class){
$class=strtolower($class);
$classFile=$_SERVER['DOCUMENT_ROOT'].'/include/class/'.$class.'.class.php';
if(is_file($classFile)&&!class_exists($class)) include $classFile;
}
}
spl_autoload_register('classAutoLoader');
?>
keyboardSmasher ¶
6 years ago
qeremy, your code is incorrect.
<?php
include_once("./myClass.php");
include_once("./myFoo.php");
include_once("./myBar.php");
$obj = new myClass();
$foo = new Foo();
$bar = new Bar();
?>
<?php
$foo = new Foo();
$bar = new Bar();
?>
should be:
<?php
$foo = new myFoo();
$bar = new myBar();
?>
eragroove at gmail dot com ¶
6 years ago
If you can keep file name and class name as same, it will be good programming practice. It helps to __autoload function to load file without checking any condition.
function __autoload($class){
require_once( $class.".php");
}
wojciech.fornal@gmail,com ¶
6 years ago
keyboardSmasher
You may or may not be right as the file name doesn't necessarily have to reflect a class name it contains (but it's usually considered a good practice). It isn't always a straightforward mapping (look at some PHP frameworks and autoload implementations).
File myBar.php may contain the class:
class Bar {
}
or it even contain the class:
class Foo {
}
Best regards
dagirovdjamal at gmail dot com ¶
2 years ago
Simple autoload :
function __autoload($class_name){
require 'class/' . $class_name . '.php';
}
ohcc at 163 dot com ¶
1 year ago
In PHP 7.2, this code will trigger a "
Deprecated: __autoload() is deprecated, use spl_autoload_register() instead in path\to\file.php on line *" error although the spl_autoload_register function really really exists.
<?php
if(!function_exists('spl_autoload_register')){
function __autoload($class){
// blah blah blah
}
}
?>
Jose G ¶
4 years ago
You should use include() or require() inside __autoload()
instead of include_once() or require_once().
If you reach __autoload(), then you know the file with the class definition has not been loaded yet.
include() and require() are more efficient than include_once() and require_once().
Ben ¶
5 years ago
Guys, this document ( i mean __autoload() ) not mentioned one special situation: if you both use __autoload() and spl_autoload_register(), the __autoload() function will never to be called. Although spl_autoload_register() documentation explained why, i decide to wrote this in case some one get confused and waste all day to figure out why.
Here is some code to verify above:
<?php
function __autoload($class) {
}
function my_loader() {
}
function your_loader() {
}
var_dump ( spl_autoload_functions () );
echo '<br/>';
spl_autoload_register ( 'my_loader' );
spl_autoload_register ( 'your_loader' );
var_dump ( spl_autoload_functions () );
romi ¶
5 years ago
<?php
if(!function_exists('classAutoLoader')){
function classAutoLoader($class){
$class=strtolower($class);
$classFile=$_SERVER['DOCUMENT_ROOT'].'/include/class/'.$class.'.class.php';
if(is_file($classFile)&&!class_exists($class)) include $classFile;
}//You have to give the class name and not the class's path for the first parameter in the class_exists()
}
spl_autoload_register('classAutoLoader');
?>
ohcc at 163 dot com ¶
5 years ago
It is highly recommended not to use the __autoload() function any more. Now the spl_autoload_register() function is what you should consider.
<?php
if(!function_exists('classAutoLoader')){
function classAutoLoader($class){
$class=strtolower($class);
$classFile=$_SERVER['DOCUMENT_ROOT'].'/include/class/'.$class.'.class.php';
if(is_file($classFile)&&!class_exists($classFile)) include $classFile;
}
}
spl_autoload_register('classAutoLoader');
?>
