Check if Headers Have Already Been Sent in PHP
Posted July 22, 2009
Most PHP programmers would have come across this old chestnut before:
Cannot modify header information – headers already sent by page.php line 42
This can happen when you try doing a HTTP redirect or send HTTP 404, as it can happen whenever you try to send headers once they’ve already been sent. When a user sees this, they are basically left high and dry, often on a blank page. The solution is simple:
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