How to disable parallel sessions on the site?

Question

PHP

How to prohibit access to the site under the same login to the 2nd user?

Answer 1

1) Solve problems that arise.
2) The need for prohibition will disappear.
3) Realize that such nonsense should not arise in the head.

Answer 2

Authorization is designed to prevent another person from logging in with your username and password
It is reliable enough if -
1) The username and password are quite complex and it is difficult to enter them accidentally and guess
2) You store your username and password securely enough
It is necessary to provide these two simple tasks and not figure out how to live when you were hacked