PHP 5.4.36 Released

interface_exists

(PHP 5 >= 5.0.2)

interface_existsPrüft ob ein bestimmtes Interface definiert wurde

Beschreibung

bool interface_exists ( string $interface_name [, bool $autoload = true ] )

Prüft ob das übergebene Interface definiert wurde.

Parameter-Liste

interface_name

Name des Interface

autoload

Bestimmt ob __autoload automatisch ausgeführt werden soll.

Rückgabewerte

Gibt TRUE zurück wenn das durch interface_name bezeichnete Interface definiert ist, sonst FALSE.

Beispiele

Beispiel #1 interface_exists() Beispiel

<?php
// Prüft ob ein Interface existiert bevor es benutzt wird
if (interface_exists('MyInterface')) {
    class 
MyClass implements MyInterface
    
{
        
// Methoden
    
}
}

?>

Siehe auch

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User Contributed Notes 3 notes

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1
maxim at inbox dot ru
2 years ago
If you want to check for included interface and you already register spl autoloader - it will crash. Becassue autoloader trying to load `string` and he doesnt matter is it class or not.
Iv found several ways :
1 - unregister AL - -> check for Ifaces - -> register Autoloader

2 - $ifaces = array_flip(get_declared_interfaces());
if($ifaces["MyIface"]) // empty // isset .

Interfaces are not bad, you can build correct geomentry of system , with validation by funcs / vars / const .
Also they are good to storage variables <?php
ROOT
::THEMES ; ROOT::LOC ; ?> . Much faster then Define, but you cant put algorithms inside, only complite strings / __file__ / etc.
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0
nils dot rocine at gmail dot com
3 years ago
A little note on namespaces that may be obvious to some, but was not obvious to me.

Although you can make the below statement when the statement is in the same namespace as the interface/class declaration MyInterface...
<?php
$foo
instanceof MyInterface
?>

Making use of the interface_exists, or class_exists functions, you must enter the full namespaced interface name like so (even if the function call is from the same namespace.)
<?php
interface_exists
(__NAMESPACE__ . '\MyInterface', false);
?>
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0
andrey at php dot net
10 years ago
As far as I remember interface_exists() was added in 5.0.2 . In 5.0.0 and 5.0.1 class_exists() used to return TRUE when asked for a existing interface. Starting 5.0.2 class_exists() doesn't do that anymore.
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