1.ini_get() gets the configuration parameters and ini_set() sets the configuration parameters

<?php
echo ini_get('display_errors'); //1
// The dynamic change php.ini Configuration information, script execution invalidated
ini_set('display_errors',0);
echo ini_get('display_errors');//0

ini_get_all() gets all configuration information

<?php
// Print all configuration information, huge amount...
print_r(ini_get_all());

3.ini_restore() restores configuration information to the original value

<?php
echo ini_get('display_errors'); //1
// The dynamic change php.ini Configuration information, script execution invalidated
ini_set('display_errors',0);
ini_restore('display_errors');
echo ini_get('display_errors');//1