スタックハウとは何ですか？

A PHP Error was encountered

Severity: Notice

Message: Undefined index: userid

Filename: views/question.php

Line Number: 190

Backtrace:

File: /home/stackhow/public_html/application/views/question.php
Line: 190
Function: _error_handler

File: /home/stackhow/public_html/application/controllers/Questions.php
Line: 420
Function: view

File: /home/stackhow/public_html/index.php
Line: 317
Function: require_once