How can the error "Cannot modify header information - headers already sent" be resolved in PHP?

The error "Cannot modify header information - headers already sent" occurs when there is output sent to the browser before PHP attempts to modify header information, such as using functions like header() or setcookie(). To resolve this issue, make sure there is no output (including whitespace) before sending headers and consider using ob_start() to buffer output if necessary. 

<?php
ob_start(); // Start output buffering

// Your PHP code here

ob_end_flush(); // Flush output buffer

Keywords

output buffering ob_start ob_end_flush header error_reporting

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