title: NOT typical PHP headers warning
body: <p>I have seen headers warnings before due to HTML or a space or in the file before sending headers. I know to avoid that. I have a file that generates an XML file and I can <strong><em>successfully</em></strong>  set the content-type as XML when I run it <em>on my localhost</em>. When I run it on <em>my production server</em>, I get the "headers already sent" warning. </p>
  
  <p>My suspicion is that something on the server is running before the file (even though I address the file directly, not as an include). I suspected WordPress so, to hopefully avoid this, I created a subdomain and placed the file there to no avail. </p>
  
  <p><em>How can I detect if something is loading before the file on the server?</em> Does WordPress take over the whole domain, subdomains and all? If so, is there a way to prevent this? I want this to run outside of WordPress.</p>