Headers already sent in Magento

[trev]

I get the following when viewing a category page in Magento:

</pre>
2014-02-05T06:28:00+00:00 DEBUG (7): HEADERS ALREADY SENT: <pre>[0] /vagrant/app/code/core/Mage/Core/Controller/Response/Http.php:52
[1] /vagrant/lib/Zend/Controller/Response/Abstract.php:766
[2] /vagrant/app/code/core/Mage/Core/Controller/Response/Http.php:83
[3] /vagrant/app/code/core/Mage/Core/Controller/Varien/Front.php:184
[4] /vagrant/app/code/core/Mage/Core/Model/App.php:354
[5] /vagrant/app/Mage.php:684
[6] /vagrant/index.php:87
</pre>

I've identified the issue to be somewhere around VafJs_Submits and VafJs_Loader_Ajax classes in vafAjax.js.include.php.

If you add a a simple return "test"; statement right after the function main() { declaration for both classes you don't get any Headers already sent... mesage. Which I supposed indicates that the problem reside in include().

I'm pretty stumped to be honest, I also don't understand why you use output buffering and not just return a string from a a wrapping function in your included file.

[trev]

Ok, so I understand a bit more about what's going on but I'm still stumped as to why the headers are already sent.

Further debugging reveals 2014-02-05T23:46:39+00:00 DEBUG (7): Cannot send headers; headers already sent in /vagrant/app/code/local/Elite/vendor/vehiclefits/library/library/VF/html/vafAjax.js.include.php, line 95

Which is consistent with what I wrote/discovered above. I just can't pinpoint what's causing the issue.

[trev]

@kylecannon I'd be happy to donate some $$ if you can help me solve this issue.

[kylecannon]

Even though this error occurs it technically doesn't cause any harm. I will see what I can do to get the error to subside.

[trev]

Thanks @kylecannon

[krishana]

I have already fixed this error in my current project.

For error track need some changes in core files

Follow this link
http://codegento.com/2011/03/debugging-headers-already-sent-error/

Now check var/log/system.log file.

In log file you get exact file path and check that.

I hope it will help you.