headers_sent

Checks if or where headers have been sent.

headers_sent Function synopsis

headers_sent(&$filename = null, &$line = null): bool

Parameters

$filename

Passed by reference, OptionalDefault valuenull

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

Passed by reference, OptionalDefault valuenull

The line number where the output started.

Note that the parameters $filename and $line are passed by reference, and contain additional/updated context data that may be useful.

Return value

Typebool

headers_sent will return false if no HTTP headers have already been sent or true otherwise.