php constant can be referenced but defined() returns false

Question

Has anyone encountered this?

var_dump(CRYPT_SHA256 == 1); // returns bool(true)
var_dump(defined(CRYPT_SHA256)); // returns bool(false)

Answer 1

defined('CRYPT_SHA256')

否则，你问的是CRYPT_SHA256常量的值是否也是另一个常量的名称....

defined(CRYPT_SHA256) === defined('1');

Answer 2

The first statement also return false for me.

I have changed it a little bit, see below

define('CRYPT_SHA256',1);
  //var_dump(CRYPT_SHA256 == 1); // returns bool(true)
  var_dump('CRYPT_SHA256');
var_dump(defined('CRYPT_SHA256')); // returns bool(false)