CODEWITHSUNDEEP
phpfunctionfunction-signature
Roland Seuhs
Roland Seuhs

Reputation: 1995

Pass default value instead of reference

I have a function like this (using PHP 7.1):

function myfunction(&$first = null, $second = null)
{   // do something
}

What I want to achieve is to pass null as the first parameter and pass something as the second parameter:

myfunction(null, $something);

When I do that I get the "Only variables can be passed by reference" error.

But of course, null is the default of the first parameter, so the function was designed to handle null as the first parameter.

Is there a way to do it?

Upvotes: 3

Views: 257

Answers (2)

mega6382
mega6382

Reputation: 9396

Instead of sending null, you can send an undeclared variable, like (DEMO):

<?php
function myfunction(&$first = null, $second = null)
{   // do something
}
myfunction($null, $something);

This will serve the purpose of executing the function and not breaking your code.

PHP 8+:

In PHP 8 we have Named Parameters, so we don't even need to pass the $first param if we don't want to (DEMO):

<?php
function myfunction(&$first = null, $second = null)
{   // do something
}
myfunction(second: $something);

Upvotes: 7

sridesmet
sridesmet

Reputation: 895

Not possible. A reference cannot be empty as first parameter if the function has more than 1 parameter.

Here are some possibilities:

function func($a = null, &$b = null) {}
function funcb(&$a, $b = null) {}

calling:

$a = null;
func($a, $b)
funcb($a)

Upvotes: 0

Related Questions