When using PHP as an Apache module, you can also change the
     configuration settings using directives in Apache configuration
     files (e.g. httpd.conf) and .htaccess files. You will need
     "AllowOverride Options" or "AllowOverride All" privileges to do so.
    
     With PHP 4 and PHP 5, there are several Apache directives that allow you
     to change the PHP configuration from within the Apache configuration
     files.  For a listing of which directives are 
     PHP_INI_ALL, PHP_INI_PERDIR, 
     or PHP_INI_SYSTEM, have a look at the
     List of php.ini directives appendix.
    
Note: 
      With PHP 3, there are Apache directives that correspond to each
      configuration setting in the php3.ini name,
      except the name is prefixed by "php3_".
     
     
- php_value
        name
        value
 
         Sets the value of the specified directive.
         Can be used only with PHP_INI_ALL and PHP_INI_PERDIR type directives.
         To clear a previously set value use none as the value.
        
Note: 
          Don't use php_value to set boolean values.
          php_flag (see below) should be used instead.
         
- php_flag
        name
        on|off
 
         Used to set a boolean configuration directive.
         Can be used only with PHP_INI_ALL and
         PHP_INI_PERDIR type directives.
        
- php_admin_value
        name
        value
 
         Sets the value of the specified directive.
         This can not be used in .htaccess files.
         Any directive type set with php_admin_value
         can not be overridden by .htaccess or virtualhost directives.
         To clear a previously set value use none as the value.
        
- php_admin_flag
        name
        on|off
 
         Used to set a boolean configuration directive.
         This can not be used in .htaccess files.
         Any directive type set with php_admin_flag
         can not be overridden by .htaccess or virtualhost directives.
        
 
    
     
Example 9-2. Apache configuration example <IfModule mod_php5.c>
  php_value include_path ".:/usr/local/lib/php"
  php_admin_flag safe_mode on
</IfModule>
<IfModule mod_php4.c>
  php_value include_path ".:/usr/local/lib/php"
  php_admin_flag safe_mode on
</IfModule>
<IfModule mod_php3.c>
  php3_include_path ".:/usr/local/lib/php"
  php3_safe_mode on
</IfModule>  |  
  | 
    | Caution | 
      PHP constants do not exist outside of PHP. For example, in 
      httpd.conf you can not use PHP constants 
      such as E_ALL or E_NOTICE 
      to set the error_reporting 
      directive as they will have no meaning and will evaluate to
      0. Use the associated bitmask values instead.
      These constants can be used in php.ini
       | 
      When running PHP on Windows, the configuration values can be
      modified on a per-directory basis using the Windows registry. The
      configuration values are stored in the registry key 
      HKLM\SOFTWARE\PHP\Per Directory Values, 
      in the sub-keys corresponding to the path names. For example, configuration 
      values for the directory c:\inetpub\wwwroot would
      be stored in the key HKLM\SOFTWARE\PHP\Per Directory
      Values\c\inetpub\wwwroot. The settings for the
      directory would be active for any script running from this
      directory or any subdirectory of it. The values under the key
      should have the name of the PHP configuration directive and the
      string value. PHP constants in the values are not parsed. 
      However, only configuration values changeable in PHP_INI_USER can be set
      this way, PHP_INI_PERDIR values can not.
     
     Regardless of how you run PHP, you can change certain values at runtime
     of your scripts through ini_set(). See the documentation
     on the ini_set() page for more information.
    
     If you are interested in a complete list of configuration settings
     on your system with their current values, you can execute the
     phpinfo() function, and review the resulting
     page. You can also access the values of individual configuration
     directives at runtime using ini_get() or
     get_cfg_var().