Reading Configuration Variables in PHP

You want to get the value of a PHP configuration setting.

Use ini_get():

To get all the configuration variable values in one step, call ini_get_all(). It returns the variables in an associative array, and each array element is itself an associative array.
The second array has three elements: a global value for the setting, a local value, and an access code:

This prints:

The global_value is the value set from the php.ini file; the local_value is adjusted to account for any changes made in the web server’s configuration file, any relevant .htaccess files, and the current script.

The value of access is a numeric constant representing the places where this value can be altered.

Table 20-1 explains the values for access. Note that the name access is a little misleading in this respect because the value of the setting can always be checked, but not always adjusted.
Table 20-1. Access values

A value of 6 means the setting can be changed in both the directory and system level, as 2 + 4 = 6.

In practice, there are no variables modifiable only in PHP_INI_USER or PHP_INI_PERDIR, and all variables are modifiable in PHP_INI_SYSTEM, so everything has a value of 4, 6, or 7.
You can also get variables belonging to a specific extension by passing the extension name to ini_get_all():

By convention, the variables for an extension are prefixed with the extension name and a period. So all the session variables begin with session. and all the PDO variables begin with pdo, for example.
Because ini_get() returns the current value for a configuration directive, if you want to check the original value from the php.ini file, use get_cfg_var():

The value returned by get_cfg_var() is the same as what appears in the global_val ue element of the array returned by ini_get_all().