How do I debug a PHP WSOD?

Question

Very occasionally I get a mystifying white-screen-of-death PHP error - nothing is displayed or logged, even with the following settings:

ini_set("error_reporting",E_ALL);
ini_set("display_errors",true);
ini_set("log_errors",true);
ini_set("display_startup_errors",true);
ini_set("html_errors",false);
ini_set("error_log","/var/log/php_error_log");

I read somewhere that output buffering or memory limit errors can result in no error output, but previously (for example) I have found a WSOD simply caused by __autoload() looking for a missing class file.

Has anyone found a way to get these errors visible? I hate commenting out blocks of code.

Thanks

Do not add settings specifically to your application unless there application dependant, you shuld modify the php.ini file and restart your web server, as a lot of the time it does not override the ini. — RobertPitt

radman radman · Accepted Answer · 2010-10-12T04:45:07

I had a similar problem recently and it turned out that the software package I was using was overriding the logging settings so that I was never seeing the logs in certain situations. Because your putting the settings in the ini file, i'm guessing your using php.ini, there is a lot of opportunity that something closer to where the code is run is changing the settings.

My advice would be to put error_reporting(E_ALL | E_STRICT); in the file that is causing the problem and see if that improves things.

How do I debug a PHP WSOD?

1 Answers