interface_exists

(PHP 5 >= 5.0.2, PHP 7)

interface_exists인터페이스가 정의되었는지 확인

설명

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

주어진 인터페이스가 정의되었는지 확인합니다.

인수

interface_name

인터페이스명

autoload

__autoload 호출 여부, 기본값은 꺼짐

반환값

주어진 interface_name이 정의되었으면 TRUE, 아니면 FALSE를 반환합니다.

예제

Example #1 interface_exists() 예제

<?php
// 사용하기 전에 인터페이스가 존재하는지 확인
if (interface_exists('MyInterface')) {
    class 
MyClass implements MyInterface
    
{
        
// 메쏘드
    
}
}

?>

참고

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User Contributed Notes 4 notes

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4
andrey at php dot net
19 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.
up
3
CoR
8 years ago
Class and Interface share SAME namespace!

class k{}

interface k {}    // Fatal error: Cannot redeclare class k
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1
maxim at inbox dot ru
11 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.
up
0
nils dot rocine at gmail dot com
12 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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