headers already sent ... ???

[Jinkowon]

Anyone can explain what happen with notive below ?

Warning: Cannot modify header information - headers already sent by

the original code is here ...

  function authenticate() {
    header('WWW-Authenticate: Basic realm="Test Authentication System"');
    header('HTTP/1.0 401 Unauthorized');
    echo "You must enter a valid login ID and password to access this resource\n";
    exit;
  }

[laserlight]

Output cannot be written before the last header is sent using e.g. header(), setcookie() etc.

You either construct your code such that output (i.e. text, HTML, blank lines) is written after your header(), or you use output buffering.

[Jinkowon]

Thank you very much. But this problem I dont really understand. Can you give me some ideas to fix it ?

[laserlight]

Test and contrast these two examples:

<?php
echo "Hello World!";
header("Location: http://example.com");
?>

<?php
header("Location: http://example.com");
echo "Hello World!";
?>

Of course, more realistically you would not be using HTTP 302 re-direction, but say you will be setting a cookie.

[devinemke]

you should also do some basic reading on headers

[Jinkowon]

Thank laserlight and devinemke 😉 . Now i know what happen with my problem. I have to configure the php.ini file.

"output_buffering" have to turn on, not off 🙂

Thank you,