PHP: How to change configuration settings - Manual to change php settings configs

Running PHP as an Apache module ¶

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.

 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.

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 ini_set(). 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 ini_set().

Example #1 Apache configuration example

<IfModule mod_php5.c>
  php_value include_path ".:/usr/local/lib/php"
  php_admin_flag engine on
</IfModule>
<IfModule mod_php4.c>
  php_value include_path ".:/usr/local/lib/php"
  php_admin_flag engine on
</IfModule>

PHP: How to change configuration settings - Manual