PHP session novice, error

Question

so I am attempting to use sessions... I get this error:

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /home1/####/public_html/####/index.php:3) in /home1/####/public_html/####/index.php on line 4

index.php:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<?php
    session_start();
    echo $_SESSION['logged_in'];
    echo $_SESSION['logged_user'];
?>
<head>

Any Idea why this might be happening?

this is asked most days here, please search first – Jan 28 '14 at 19:48 — , Jan 28 '14 at 19:48
Try starting the session before you send the doctype etc – RyanS Jan 28 '14 at 19:49 — RyanS, Jan 28 '14 at 19:49

score 6 · Accepted Answer · answered Jan 28 '14 at 19:48

Once you output HTML, or any content, PHP can no longer send the headers required to use sessions (i.e. set cookies). You must call session_start() before any output is generated from your script:

<?php
    session_start();
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<?php
    echo $_SESSION['logged_in'];
    echo $_SESSION['logged_user'];
?>
<head>

please mark as duplicate rather than answering, you dont need the rep points ;-) — , Jan 28 '14 at 19:49

score 1 · Answer 2 · answered Jan 28 '14 at 19:48

1

You cannot send headers (like session_start) after you already output content.

answered Jan 28 '14 at 19:48

qwertynl

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PHP session novice, error

2 Answers2