[RESOLVED] Problem with session_start();

[crusty]

The code below works fine on my PHP enabled web site.
On my home computer (wamp installed) I get the error message:-

"Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at c:\wamp\www\Mesh4Us\Htdocs\AlecHall\session1.php:2) in c:\wamp\www\Mesh4Us\Htdocs\AlecHall\session1.php on line 3".

What am I doing wrong please and how do I overcome it.
Regards
crusty
------------------------------------- code used ----------------
<?php
session_start();

if ($SESSION["last_visit"]) { echo "Date of last visit: ";
echo date("j F Y, H:i:s", $SESSION["last_visit"]); echo "<br>"; echo "Total visits: ".$SESSION["num_visits"];
} else
echo "This is your first visit";
$SESSION["last_visit"] = time();
$_SESSION["num_visits"]++;

?>

[bradgrafelman]

Are there any spaces or blank lines before the <?php tag?

Can you attach session1.php as a .txt file to your next post? (Don't forget to remove any sensitive information - i.e. credentials - from the script when you do.)

[crusty]

Thanks!

There was indeed a blank line before the first <?PHP

I've removed it and it now works. Wish I knew why but I'm a pragmatic old Crusty so it doesn't really matter.
Thanks again.
Regards

[NogDog]

The error will happen if anything is output before the call to session_start(). That "anything" can include any text not within the <?php...?> tags, including spaces, tabs, newlines, or carriage returns. This is because as soon as anything is sent to the browser, all pending HTTP headers are first sent at that time. After that first output, no more HTTP headers can be sent, and since session_start() needs to send some HTTP headers (mainly for the session ID cookie), it cannot execute.

[bradgrafelman]

Don't forget to mark this thread resolved (if it is).

[crusty]

Thanks. I'd now like to mark this as RESOLVED but I can't find 'Thread Tools' anywhere.
Thanks again.