Coalesce Operator

The coalesce operator ?? returns its first operand if it is set and not NULL. Otherwise it will return its second operand.

<?php

    class X { }

    // instantiation
    $x = new X;

    // cloning
    $y = clone $x;

?>

Documentation

See also Null Coalescing Operator (??) and PHP ternary operator vs null coalescing operator.

Related : Ternary Operator, Colon, If Then Else, Short Ternary Operator, Conditional Structures, Double, Nullsafe, Question Mark ?, Streamlining

Added in PHP 7.0+