(PHP 7 >= 7.1.0, PHP 8)
ReflectionClass::getReflectionConstants — Gets class constants
$filter = null): arrayRetrieves reflected constants.
filterThe optional filter, for filtering desired constant visibilities. It's configured using the ReflectionClassConstant constants, and defaults to all constant visibilities.
An array of ReflectionClassConstant objects.
| Version | Description | 
|---|---|
| 8.0.0 | filterhas been added. | 
Example #1 Basic ReflectionClass::getReflectionConstants() example
<?php
class Foo {
    public    const FOO  = 1;
    protected const BAR  = 2;
    private   const BAZ  = 3;
}
$foo = new Foo();
$reflect = new ReflectionClass($foo);
$consts  = $reflect->getReflectionConstants();
foreach ($consts as $const) {
    print $const->getName() . "\n";
}
var_dump($consts);
?>
The above example will output something similar to:
FOO
BAR
BAZ
array(3) {
  [0]=>
  object(ReflectionClassConstant)#3 (2) {
    ["name"]=>
    string(3) "FOO"
    ["class"]=>
    string(3) "Foo"
  }
  [1]=>
  object(ReflectionClassConstant)#4 (2) {
    ["name"]=>
    string(3) "BAR"
    ["class"]=>
    string(3) "Foo"
  }
  [2]=>
  object(ReflectionClassConstant)#5 (2) {
    ["name"]=>
    string(3) "BAZ"
    ["class"]=>
    string(3) "Foo"
  }
}