International PHP Conference Berlin 2025

trait_exists

(PHP 5 >= 5.4.0, PHP 7, PHP 8)

trait_existsVérifie si un trait existe

Description

trait_exists(string $trait, bool $autoload = true): bool

Liste de paramètres

trait

Nom du trait à vérifier

autoload

S'il faut ou non charger automatiquement s'il n'a pas déjà été chargé.

Valeurs de retour

Retourne true si le trait existe, et false sinon.

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User Contributed Notes 3 notes

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9
Lubaev.K
11 years ago
<?php
trait World {

private static
$instance;
protected
$tmp;

public static function
World()
{
self::$instance = new static();
self::$instance->tmp = get_called_class().' '.__TRAIT__;

return
self::$instance;
}

}

if (
trait_exists( 'World' ) ) {

class
Hello {
use
World;

public function
text( $str )
{
return
$this->tmp.$str;
}
}

}

echo
Hello::World()->text('!!!'); // Hello World!!!
up
0
astinus dot eberhard at gmail dot com
7 years ago
Traits are compatible with class autoload mechanism - in fact, if you look at source code of trait_exists function, you will find similar peace of code (see Zend/zend_builtin_functions.c)
up
-1
valerio dot bozzolan at gmail dot com
8 years ago
What is the default value of $autoload? And in which way traits are autoloaded? Is there something as spl_autoload() for traits?
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