Inserting code via include() echoes content
<p>I'm a little bit confused by the behaviour of the <code>include()</code> (and all related) functions.  If I have a file <code>library.php</code>, which contains some code (in my case, a single array):</p>

<pre><code>&lt;?php
$exampleArray = array(
    "Item1" =&gt; "Item 1 description",
    "Item2" =&gt; "Item 2 description"
);
?&gt;
</code></pre>

<p>and I want to be able to access that array in another file (<code>index.php</code>), then in <code>index.php</code> I need to do <code>require_once('library.php');</code>.  If I don't have the PHP tags, then the code is echoed. However, <a href="http://www.php.net/manual/en/function.include.php#103011" rel="nofollow">this comment on the PHP site</a> implies that, regardless of whether the tags are included or not, if the header of the included file is modified, the content will be echoed.</p>

<ol>
<li>Is this right? If I change the file I want to include to <code>library.txt</code>, but still have the PHP tags, the content isn't echoed (although I realise the content type is still almost certainly <code>text/plain</code> in both cases)</li>
<li>The comment also says 'It only takes a single wrong character to show everyone in the world that information.' - what single wrong character is he referring to?  </li>
</ol>
