Yield, Not Return By Reference

<?php

function &gen() {
    yield 'foo';
    
    return 'Literal';
}

$gen = gen();
var_dump($gen->current());


foreach($gen as $a) {
    print $a;
}

print $gen->getReturn();

?>

When a method returns a reference, there is a & before its name, in the signature. This means that the function must return a variable, or a property, and not a literal value.

When the same & is added on a generator, this now means that the yielded values are by reference. On the other hand, the returned value mat be a literal value, without generating a warning.

See Also

• Generator syntax
• Returning value
• No reference for yield [Try me]

PHP Features

• reference
• generator
• yield

Last updated: 10 September 2026