Something to watch look for when getting HEADER Warnings

Recently, I ran into a problem where I continually got a "Header already sent" message. I took me a while to figure out because the file that was "included" only contained function definitions, or so I thought. After the closing php tag, I had a new line with a single space on it. This space was, in turn, sent to the browser. ---- file.php begin (blah, not working) ----- <?php function seomthing() { //do something } ?>[enter] [space] ---- file.php end ------ It wasn't until I removed the single space and any additional newlines that all worked fine. Any non-null lines outside of the php tags will results in voiding all rights to send any header or cache information, and this includes space or newline characters. Just an FYI. ---- file.php begin (cool, it works now) ----- <?php function seomthing() { //do something } ?>[no newline] ---- file.php end ------ Actually, you can have a newline after the clsoing php tab, but if you have a non-null string following that (this includes newline characters), bad bad stuff can happen.