More information about the Underscore mailing list

[_] Error : PHP Warning: Cannot modify header information - headers already sent

Jeremy Prior jeremy.prior at
Mon Mar 19 10:02:41 GMT 2018

On Mon 19 Mar 2018, at 09:29:50, Martin Moore <martinm at> wrote:
> Turns out I needed ob_start and ob-flush.
> The odd thing is it was working at one point....

Output buffering would fix it, but I'd use it as a last resort.  It captures your entire page and doesn't output anything until you've finished processing.  This means that there will be a delay before the browser can render anything, which on a large page could be noticeable.  You are better off reorganising the logic of your page if that's possible. 

Jeremy Prior