PHP uninitialized variable evaluation


php > $user;
php > print var_dump(!$user);
PHP Notice: Undefined variable: user in php shell code on line 1
bool(true)
php > print var_dump($user);
PHP Notice: Undefined variable: user in php shell code on line 1
NULL
php > print var_dump(empty($user));
bool(true)




uninialized variable evaluates to NULL (with notice)

!$var evaluates to True

empty($var) evaluates to True