How do I do a "Log Off" link ??

[spacepoet]

Hi again:

 

How do I do a proper log off link, to destroy the session from the initial login to the admin area, and then redirect the user back to the login page?

 

I have a link called "Log Off" which goes to a page "a_LogOff.php" and this is the code:

<?
session_destroy();
header("location:Login.php");
?>

 

I am use to ASP and doing it this way:

<%
session.abandon
response.redirect "Login.asp"
%>

 

Which works fine and is pretty easy.

 

Doing it in PHP keeps giving me this error:

Warning: session_destroy() [function.session-destroy]: Trying to destroy uninitialized session in /admin/a_LogOff.php on line 2

Warning: Cannot modify header information - headers already sent by (output started at admin/a_LogOff.php:2) in admin/a_LogOff.php on line 3

 

I thought this would be the easy part of the project, but apparently I am mistaken ...

 

Anyone know how to do this?

[trq]

You need to call session_start() prior to using any other session functions.

[spacepoet]

Well, I had tried that.

 

This is the original code for that:

// Put this code in first line of web page.
<?
session_start();
session_destroy();

header("location:login.php");
?>

 

But I keep getting this error:

// Put this code in first line of web page.
Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /admin/a_LogOff.php:2) in /admin/a_LogOff.php on line 3

Warning: Cannot modify header information - headers already sent by (output started at /admin/a_LogOff.php:2) in /admin/a_LogOff.php on line 6

 

Any idea why?

[suma237]

remove the comment  and also the space

// Put this code in first line of web page.

 

[trq]

Something must be sending output to the browser. There is a sticky in this board which covers the subject.

[spacepoet]

Yes!

 

Thanks. It was the comment and space (didn't think a space would cause an issue ... odd):

<?
session_start();
session_destroy();
header("location:Login.php");
?>

 

Thanks much, everyone, for the help!