In this quick post to his blog Mattias Geniar looks at three different Apache flags you can use in your configuration/.htaccess files to set various things in your PHP environment.

Back in 2009 there was a bug in the php_admin_value implementation before PHP 5.2.6. Since then, everything should run smoothly again. However, I find there's still a lot of confusion on when to use php_value, php_admin_value, php_flag and php_admin_flag. So I'll see if we can clear some of that.

He compares the three php_* flags you can use to set different kinds of values - "php_flag" for boolean operations, "php_admin_flag" (similar, but only in the vhost config) and the "php_value" that can be used for everything else, including overriding some settings in your php.ini.

Cal Evans came up against a problem earlier in his development work - issues when he was trying to get his old include path.

What you SHOULD get back is a string describing your old include path. If you get false, you have hit the problem I hit last night. I went so far as to recompile 2 difference versions of Apache thinking (almost correctly) that it was something that had changed in my Apache config files.

If you're one of the "falsers" out there, check out the rest of his post of his solution around the problem. His problem stemmed from his trying to reassign a php_admin_value (instead of php_value where the script could override it) setting, specifically the one for the include_path.

He also points out that Zend Framework users might keep an eye out for this problem too as the Zend_Loader package changes the include path at times.