headers already sent issue

Question

Possible Duplicate:
“Warning: Headers already sent” in PHP

Looking at the other threads relating to this error I can't seem to locate my issue. I don't have any output prior to the call so can anyone tell me what the issue is?

Error is:

Warning: Cannot modify header information - headers already sent by ... line 12

Here is the PHP code:

<?php if (!isset($_SESSION)) session_start();

require_once 'classes/mobile_detect.class.php';

$detect = new Mobile_Detect;
if ($detect->isMobile()) {
    $referer = 'http://my_site_name/m/index.php';

    header("Location: " . $referer);
    exit();
}     
?>

<!DOCTYPE html>
<html lang="en">
<head>
...

What's your file's character encoding? Double check that you don't have a byte order mark. — Major Productions, Dec 06 '12 at 02:04

score 2 · Accepted Answer · answered Dec 06 '12 at 02:07

2

could very well be whitespace (or other output) in classes/mobile_detect.class.php

answered Dec 06 '12 at 02:07

Patrick Moore

13,251
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That was painful, not sure if was white space or something else. I opened it up in a text editor and cleaned it. Working now. Thanks! – Paul Dec 06 '12 at 02:12

score 1 · Answer 2 · answered Dec 06 '12 at 02:07

1

Open the file in a hex editor and make sure you don't have a byte order mark in the beginning of the file.

answered Dec 06 '12 at 02:07

Michael

930
5
8

score 1 · Answer 3 · edited May 23 '17 at 12:12

1

Never use a closing php tag ?> in library files. There not needed and can cause this kind of issues.

For a more complete answer, please read Why do some scripts omit the closing PHP tag, '?>'?

edited May 23 '17 at 12:12

Community

1
1

answered Dec 06 '12 at 02:30

Arnold Daniels

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4
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headers already sent issue

3 Answers3