What does this php operator do?

Question

$serial = ($_SERVER['SSL_CLIENT_M_SERIAL'] ?? false);

It looks like a bit like a ternary. But for that I would have expected:

$serial = $_SERVER['SSL_CLIENT_M_SERIAL'] ?  $_SERVER['SSL_CLIENT_M_SERIAL'] : false

perhaps it's shorthand, but finding a link to confirm is difficult. I found the snippet in php4 legacy code.

(note this is php not c#)

_“but finding a link to confirm is difficult”_ - typing “php double question mark” into Google would have lead you to the duplicate in no time … — CBroe, May 14 '18 at 13:59
thanks, knowing what to search for is half the battle. I was trying '??' instead of 'double question mark — Techbot, May 14 '18 at 14:19

score 1 · Answer 1 · answered May 14 '18 at 13:59

1

I found the snippet in php4 legacy code

That's weird. As far as I know, it was added in PHP 7.

From the docs:

The null coalescing operator (??) has been added as syntactic sugar for the common case of needing to use a ternary in conjunction with isset(). It returns its first operand if it exists and is not NULL; otherwise it returns its second operand.

answered May 14 '18 at 13:59

Loek

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you are correct, it is legacy code, but this line is newer. thanks. – Techbot May 14 '18 at 14:18

score -5 · Answer 2 · answered May 14 '18 at 13:58

-5

its what to do if

    if null

a link ps: you're welcome thanks for the minus 2, loads of languages use this, most notably swift

answered May 14 '18 at 13:58

Mr Heelis

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seriously why the double minus for answering the question within 12 seconds correctly? – Mr Heelis May 14 '18 at 14:01
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1) If it's a duplicate, vote to close as duplicate. 2) "its what to do if if null" is a terrible answer. – deceze May 14 '18 at 14:01
`What does this php operator do? ` ... `it's what to do if if null` – Mr Heelis May 14 '18 at 14:02

What does this php operator do?

2 Answers2