Question

PHP manual says you have to do sort($array). $array will be passed by reference, so sort() will modify $myArray.

I’m just wondering if there is any problem or implication if you do sort(&$myArray).

Answer 1

To give a more detailed answer:

• It’ll work without issues in PHP 5.2 and before.
• It’ll trigger an E_DEPRECATED warning (sometimes) on PHP 5.3
• It is very likely to stop working on PHP 5.4. (Which alternates between refusal and memory violation errors. Not finalized yet, but that change is likely to stay.)

The reasoning for deprecating pass-by-references is diffuse. It’s mostly code-cleanliness. Secondly it was commonly misused by newcomers, leading to side-effects if unsupervised. (If newcomer misuse ever was a good reason for deprecation, then mysql_query should have been long gone.)
And thirdly, there are in fact some internal memory management issues with passing parameters by reference when the ZendVM does not expect it. (Quercus and Project Zero do not have such issues.)