php: session_start() error
<p>I have a file, which starts <code>&lt;?php session_start();?&gt;</code>, and it returns an error</p>

<pre><code>Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at C:\xampp2\htdocs\index.php:1) in C:\xampp2\htdocs\index.php  on line 3
</code></pre>

<p>and now take a look at the  moment, i can't anderstand anyway
when i copy the all content of my file into another file, it start working.
can somebody explain how can it happen.
thanks</p>

<h2>update</h2>

<p><strong>i havent't any white spaces, at least i can't see them</strong></p>
