ReflectionReference::getId

Get unique ID of a reference

&reftitle.description; public `string` `ReflectionReference::getId`

Returns an ID which is unique for the reference for the lifetime of that reference. This ID can be used to compare references for equality, or to maintain a map of known references.

&reftitle.parameters; &no.function.parameters;
&reftitle.returnvalues;

Returns a &string; of unspecified format.

&reftitle.examples;

### Basic `ReflectionReference::getId` usage

    <?php
    $val1 = 'foo';
    $val2 = 'bar';
    $arr = [&$val1, &$val2, &$val1];

    $rr1 = ReflectionReference::fromArrayElement($arr, 0);
    $rr2 = ReflectionReference::fromArrayElement($arr, 1);
    $rr3 = ReflectionReference::fromArrayElement($arr, 2);

    var_dump($rr1->getId() === $rr2->getId());
    var_dump($rr1->getId() === $rr3->getId());
    ?>

&example.outputs;

    bool(false)
    bool(true)