PHP Function Reference

PHP trait_exists() Function

The PHP trait_exists() function is used to check whether or not the given trait has been defined.


trait_exists(trait, autoload)


trait Required. Specify the trait name to check. The name is matched in a case-insensitive manner.
autoload Optional. Specify whether to autoload if not already loaded.

Return Value

Returns true if trait exists, false if not, null in case of an error.

Example: trait_exists() example

The example below shows the usage of trait_exists() function.

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;

//checking that the trait exists 
//before trying to use it
if (trait_exists('World')) {
  class Hello {
    use World;

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

echo Hello::World()->text('!');

The output of the above code will be:

Hello World!

❮ PHP Classes/Objects Reference