PHP 5.4.33 Released

__autoload

(PHP 5)

__autoloadAttempt to load undefined class

Descrizione

void __autoload ( string $class )

You can define this function to enable classes autoloading.

Elenco dei parametri

class

Name of the class to load

Valori restituiti

Nessun valore viene restituito.

Vedere anche:

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User Contributed Notes 8 notes

up
29
qeremy
2 years ago
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".
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15
ohcc at 163 dot com
9 months 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');
?>
up
5
keyboardSmasher
1 year 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();
?>
up
0
eragroove at gmail dot com
1 year 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");
}
up
0
wojciech.fornal@gmail,com
1 year 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
up
-1
romi
2 months 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');
?>
up
-9
ohcc at 163 dot com
9 months 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');
?>
up
-5
Ben
5 months 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 () );
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