PHP pass array by reference

Question

What is a correct way to use array_splice in PHP? The function header clearly says:

array_splice ( array &$input , int $offset... so it should accept reference as a first argument.

However, a line

array_push(&$this->contextsIds, $contextId);

Triggers an error Deprecated: Call-time pass-by-reference has been deprecated in ... line 132
How do I return a reference to an array? I have:
```
public function &getContextsIds() {
    return is_array($this->contextsIds) ? $this->contextsIds : array();    
}
```
but it says Notice: Only variable references should be returned by reference

BoltClock · Accepted Answer · 2012-07-31 04:05:22Z

7

The function is already declared to take a reference (array &$input); you don't need the & again when calling the function. Just call it like this:
```
array_push($this->contextsIds, $contextId);
```
As the message says, you should only return actual variables by reference, not mere values. In your example, there are two such instances: the ? : operator evaluates to a value, and also array() by itself is just a value not bound to any variable. You should probably just return your class member regardless of whether it is empty or not:
```
return $this->contextIds;
```

edited Jul 31, 2012 at 4:05

BoltClock

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answered Dec 12, 2010 at 16:07

casablanca

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3 Comments

tillda Over a year ago

Thanks! Would you please help me on the second one that I've added?

BoltClock Over a year ago

"regardless of whether it is empty or not" He's testing is_array()

casablanca Over a year ago

@BoltClock: I noticed that, but I'm guessing that he is likely testing if it's empty. I'll wait for the OP's response.

GolezTrol · Accepted Answer · 2010-12-12 16:13:55Z

1

Why would you return a reference to an array, especially in the code you provided:

public function &getContextsIds() {
    return is_array($this->contextsIds) ? $this->contextsIds : array();    
}

When that function is would work, it could return a reference to an empty array, I could do with it what I want and change it as much as I'd like, but it wouldn't have any effect, because it was just an empty array without any further reference at all..

answered Dec 12, 2010 at 16:13

GolezTrol

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