interface_exists

(PHP 5 >= 5.0.2)

interface_exists — Checks if the interface has been defined

Описание

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

Checks if the given interface has been defined.

Список параметров

interface_name

The interface name

autoload

Whether to call __autoload or not by default

Возвращаемые значения

Returns TRUE if the interface given by interface_name has been defined, FALSE otherwise.

Примеры

Пример #1 interface_exists() example

<?php
// Check the interface exists before trying to use it
if (interface_exists('MyInterface')) {
    class 
MyClass implements MyInterface
    
{
        
// Methods
    
}
}

?>

Смотрите также

Коментарии

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.
2004-10-24 07:40:49
http://php5.kiev.ua/manual/ru/function.interface-exists.html
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);
?>
2011-10-26 21:35:04
http://php5.kiev.ua/manual/ru/function.interface-exists.html
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.
2012-10-01 13:40:51
http://php5.kiev.ua/manual/ru/function.interface-exists.html
Автор:
Class and Interface share SAME namespace!

class k{}

interface k {}    // Fatal error: Cannot redeclare class k
2015-11-28 16:30:40
http://php5.kiev.ua/manual/ru/function.interface-exists.html

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