Closures with PHP

Question

I have a weird problem trying to use closures in PHP. When assigning a closure to a variable, I get a null value. But when displaying the closure with var_dump(), everything is alright.

Here is a source code that summarizes the problem:

$f = function() {}; var_dump($f); // 'null' var_dump(function() {}); // 'object(Closure)[1]'

I'm using PHP 5.3.1.

Edit: I forgot to mention, I have this problem only when I'm using PHP via Apache. I don't have issues when using PHP CLI.

Weird. I'm getting this output (which is the correct one, AFAIK). — Amal
– Amal, Commented Nov 18, 2013 at 14:40
Try running that code exactly, to be sure your summary isn't different from your actual code. — John V.
– John V., Commented Nov 18, 2013 at 14:41
@Jack It must be a bug. Because I just ran the code on 5.5.1 and it works as expected. So it's... FIXED. - hence it was a bug, logic says so. Unfortunately, I'm too busy to do bug research at the moment. And this bug would never hit me as I see absolutely no reason in writing an empty closure. I usually write functions that do stuff. — CodeAngry
– CodeAngry, Commented Nov 18, 2013 at 15:04

scastiel · Accepted Answer · 2013-11-18 15:11:14Z

2

A colleague found the answer to the problem: the responsible is eAccelerator! Apparently it's not compatible with PHP 5.3 closures... (source)

Disabling it solved the problem.

Thanks for your help!

answered Nov 18, 2013 at 15:11

scastiel

954 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

CodeAngry Over a year ago

Consider updating. They claim to support 5.4 on their site. PS: Is the first time you use a closure...? They're probably the most useful PHP feature added this decade and they've been around for ONLY 4 years.

scastiel Over a year ago

If it depended on me I'll always use PHP 5.4 or 5.5, but I'm using in professional environment...

Narf · Accepted Answer · 2013-11-18 14:47:22Z

It's either a very rare (and already fixed) bug or you're not showing the exact same usage that gives you a NULL. My guess is that you're doing this with the first var_dump():

var_dump($f());

Note the parenthesis, they cause the function to be run and therefore you get its return value.

Nope, I copy-pasted the code. When I write $f() I have an error. (It's logic since $f is evaluated to null.)

Collectives™ on Stack Overflow

Closures with PHP

2 Answers 2

2 Comments

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Related