headers_sent

headers_sent

(PHP 4, PHP 5, PHP 7)

headers_sentChecks 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