Php Headers_sent

Php Headers_Sent. If the optional filename and line parameters are set headers_sent () will put the PHP source file name and line number where output started in the filename and line variables line The line number where the output started Return Values headers_sent () will return false if no HTTP headers have already been sent or true otherwise ExamplesCode sampleif (!headers_sent()) {  header(‘Location http//wwwexamplecom/’)  exit}if (!headers_sent($filename $linenum)) {Data under © The PHP documentation is Copyright by and the property of the PHP Project and the PHP Group and its inclusion in this product is not an endorsement by the PHP Project PHP Group or its subsidiaries and affiliatesWas this helpful?Thanks! .

The headers_sent () function checks if/where headers have been sent Syntax headers_sent ( fileline ) Parameter Values Technical Details More Examples Example Using the optional file and line parameters.

PHP headers_sent() Function W3Schools

PHP has to pass the headers to the webserver first It can only do that once After the double linebreak it can nevermore amend them When PHP receives the first output ( print echo ) it will flush all collected headers Afterward it can send all the output it wants But sending further HTTP headers is impossible then.