How can PHP developers avoid the headers already sent error when using header() function for redirection?

When using the header() function for redirection in PHP, developers can avoid the "headers already sent" error by ensuring that no output is sent to the browser before calling the header() function. This error occurs when PHP tries to send HTTP headers after content has already been sent to the browser. To prevent this, developers should make sure that there is no whitespace or HTML content before the header() function is called. 

<?php
ob_start(); // Start output buffering
// Any code that might output content here

// Redirect to a new page
header("Location: newpage.php");
exit();
ob_end_flush(); // Flush the output buffer
?>

Keywords

header headers already sent error output buffering ob_start

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