php - CI框架 Cannot modify header information - headers already sent by

A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at /var/www/fbz/application/models/Content.php:268)

Filename: helpers/url_helper.php

貌似把前面的

$logsession = $this->session->all_userdata();

这句去了也不会报错