Stopping PHP from sending any headers

Hi there! I am wondering if there is any way to stop PHP from sending any headers at all. I know about php -q, but unfortunately I want it to work with the module version of PHP as well. What I do is collect all output with the ob_ functions, and send it to a pipe. And there the output is encoded, headers are sent and the content is sent to stdout. However, after this is done, more headers are being sent by PHP. I want to keep it as much as possible outside the PHP code (I have my reasons :) I guess I could grab the output from the pipe, but if there's a way to make php not send any headers at all that'd be much nicer. Right now I "fixed" it by printing <!-- in the external prog, and after that --> in the php code, so at least the headers don't show up in the browser.. Nice is something else tho. Any ideas? Thanks! /Nico