headers_sent
headers_sent
(PHP 4, PHP 5, PHP 7)
headers_sent — Checks if or where headers have been sent
Description
bool headers_sent ([ string &$file [, int &$line ]] )
Checks if or where headers have been sent.
You can't add any more header lines using the header() function once the header block has already been sent. Using this function you can at least prevent getting HTTP header related error messages. Another option is to use 登录查看完整内容