Description
bool
headers_sent ( string &file [, int &line])
This function returns TRUE if the HTTP headers have already been
sent, FALSE otherwise. You can't add any more header lines using
the header() function once the header block has
already been sent. Using this function you can at least prevent
getting the "Duplicate headers ..." error messages.
The function will return the php source file and line number where
output started in the optional file and
line parameters if these are given.
Nota:
file and line where
added for PHP 4.3.0.
See also header() for a more detailed discussion
of the matters involved.
header
