====== PHP: php_value vs php_admin_value and the use of php_flag explained ======

Источник: [[https://ma.ttias.be/php-php_value-vs-php_admin_value-and-the-use-of-php_flag-explained/|PHP: php_value vs php_admin_value and the use of php_flag explained]]

===== php_flag =====

When using the **php_flag** directive in Apache configurations, it's used to set **boolean** values for options. So only true/false, On/Off, ...  kind of parameters. For example:

<code>
php_flag display_startup_errors off
php_flag display_errors off
...
</code>

Those are only On/Off values with which you enable or disable the setting. You can use the **php_flag**  option in Virtual Host configs, .htaccess files and the general Apache configuration. However, you can 't change every configuration value from PHP that way. You can only change the **PHP_INI_ALL** and **PHP_INI_PERDIR** options shown on the "[[http://www.php.net/manual/en/ini.list.php|List of php.ini directives]]" page.

===== php_admin_flag =====

This can only be used within the Apache configuration (general config or in a Virtual Host) and can not be used in a .htaccess. You can set any kind of php configuration setting that behaves as a boolean this way. For example:

<code>php_admin_flag safe_mode off</code>

By using the php_admin_flag **you can not overwrite the setting from within your application using ini_set()!** Whatever the value is there, it will remain so during the execution of your applications.

===== php_value =====

If php_flag is used for booleans, **php_value** is used for everything else. Any kind of configuration directive that takes parameters other than On/Off, you can use php_value for. For example:

<code>
php_value error_log  /some/dir/to/log/php_errors.log
php_value  upload_max_filesize  10M
...
</code>

Just the same as the php_flag, you can not overwrite all configurations this way. Since you can use **php_value** everywhere (.htaccess, apache configs & virtual host), it would be unsafe. You can only change the **PHP_INI_ALL** and **PHP_INI_PERDIR** options shown on the "[[http://www.php.net/manual/en/ini.list.php|List of php.ini directives]]" page.

If you want to clear a configuration value, use the "none" value.

<code>php_value open_basedir none</code>

===== php_admin_value =====

This option can only be used in the Apache configuration, not in .htaccess files. It does allow you to overwrite any configuration value possible in PHP.

By using the php_admin_value, **the value of that configuration directive cannot be overwritten in the application**. That means if you were to set your //include_path// by using php_admin_value, the application (such as the Zend Framework bootstrap) would not be able to alter the content of that configuration directive //via ini_set()// or //set_include_path()//.

Only use the php_admin_value if you explicitly want to forbid that configuration directive from being changed by your application.