What is the significance of the error message "Cannot add header information - headers already sent" in PHP and how can it be resolved?

The error message "Cannot add header information - headers already sent" in PHP indicates that some content has already been sent to the browser before setting headers. To resolve this issue, ensure that no output is sent to the browser before setting headers, such as using the header() function. One common cause is whitespace before the opening <?php tag or outputting content before calling header(). 

&lt;?php
ob_start(); // Start output buffering

// Your PHP code here

ob_end_flush(); // Flush output buffer

Keywords

PHP header output buffering ob_start ob_end_clean

Related Questions