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    interface_exists

    (PHP 5 >= 5.0.2, PHP 7, PHP 8)

    interface_exists — Prüft, ob ein bestimmtes Interface definiert wurde

    Beschreibung

    interface_exists(string $interface, bool $autoload = true): bool

    Prüft, ob das übergebene Interface definiert wurde.

    Parameter-Liste

    interface

    Der Name des Interfaces.

    autoload

    Gibt an, ob automatisch geladen werden soll, falls nicht bereits geladen.

    Rückgabewerte

    Gibt true zurück, wenn das durch interface 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 4 notes

    up
    7
    CoR
    8 years ago
    Class and Interface share SAME namespace!

    class k{}

    interface k {}    // Fatal error: Cannot redeclare class k
    up
    5
    andrey at php dot net
    20 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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    4
    nils dot rocine at gmail dot com
    13 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);
    ?>
    up
    2
    maxim at inbox dot ru
    12 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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