What is for(;;) in Facebook long poling request?

Question

Hi i have question which means for (;;); in Facebook long polling request ? This statement is in every file which is long polled from Facebook server.

Thank you

I know that is infinite loop but i still don't know why facebook have this statement in every Long pulled file ? — Tomáš Mihalička, Sep 24 '13 at 17:00
http://stackoverflow.com/q/2669690 may be similar, just with Google. — Jonathan Lonowski, Sep 24 '13 at 17:40

score 1 · Answer 1 · answered Sep 24 '13 at 16:51

1

This is an infinite loop. The same as while(true).

I guess they use it instead of while to make a file size smaller.

answered Sep 24 '13 at 16:51

Eugene Naydenov

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score 1 · Answer 2 · answered Sep 24 '13 at 16:51

1

in a for loop all params are optional, this is basically an infinite loop

answered Sep 24 '13 at 16:51

MichaC

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tikider · Accepted Answer · 2013-09-24T18:48:24.667

1

No way this infinite loop is executed; just try it in your console. A simple operation like integer incrementing will freeze your screen:


    var a = 1;
    for (;;) {
        a++;
    }

It may be just a small trap for anyone who tries to eval their script, or something.

edited Sep 24 '13 at 18:48

answered Sep 24 '13 at 17:06

tikider

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you're right, I believe I recall from when this came up before somewhere - this is intended as a security measure. – JAL Sep 24 '13 at 17:51

score 0 · Answer 4 · answered Sep 24 '13 at 16:58

that's an infinite loop,

for(;;) {[condition to break + loop logic]}
while ([condition to break]) { }
do { } while ([condition to break]);

for example, you can use it to repeat certain operation multiple times and it's up to you to decide when to stop iterating using a break statement. (just a fancy way of using a for instead of a do/while)

cheers!

What is for(;;) in Facebook long poling request?

4 Answers4