headers_sent(3) [php man page]

HEADERS_SENT(3) 							 1							   HEADERS_SENT(3)

headers_sent - Checks if or where headers have been sent

SYNOPSIS

       bool headers_sent ([string  &$file], [int  &$line])

DESCRIPTION

	Checks if or where headers have been sent.

	You  can't add any more header lines using the header(3) function once the header block has already been sent. Using this function you can
       at least prevent getting HTTP header related error messages. Another option is to use Output Buffering.

PARAMETERS

	      o $file
		- If the optional $file and $line parameters are set, headers_sent(3) will put the PHP source file name and line number where out-
		put started in the $file and $line variables.

	      o $line
		- The line number where the output started.

RETURN VALUES

       headers_sent(3) will return FALSE if no HTTP headers have already been sent or TRUE otherwise.

EXAMPLES

       Example #1

	      Examples using headers_sent(3)

	      <?php

	      // If no headers are sent, send one
	      if (!headers_sent()) {
		  header('Location: http://www.example.com/');
		  exit;
	      }

	      // An example using the optional file and line parameters, as of PHP 4.3.0
	      // Note that $filename and $linenum are passed in for later use.
	      // Do not assign them values beforehand.
	      if (!headers_sent($filename, $linenum)) {
		  header('Location: http://www.example.com/');
		  exit;

	      // You would most likely trigger an error here.
	      } else {

		  echo "Headers already sent in $filename on line $linenum
" .
			"Cannot redirect, for now please click this <a " .
			"href="http://www.example.com">link</a> instead
";
		  exit;
	      }

	      ?>

NOTES

       Note

	       Headers will only be accessible and output when a SAPI that supports them is in use.

SEE ALSO

       ob_start(3), trigger_error(3), headers_list(3), header(3) for a more detailed discussion of the matters involved. .

PHP Documentation Group 													   HEADERS_SENT(3)

HTTP::Request(3)					User Contributed Perl Documentation					  HTTP::Request(3)

NAME

       HTTP::Request - HTTP style request message

SYNOPSIS

	require HTTP::Request;
	$request = HTTP::Request->new(GET => 'http://www.example.com/');

       and usually used like this:

	$ua = LWP::UserAgent->new;
	$response = $ua->request($request);

DESCRIPTION

       "HTTP::Request" is a class encapsulating HTTP style requests, consisting of a request line, some headers, and a content body. Note that the
       LWP library uses HTTP style requests even for non-HTTP protocols.  Instances of this class are usually passed to the request() method of an
       "LWP::UserAgent" object.

       "HTTP::Request" is a subclass of "HTTP::Message" and therefore inherits its methods.  The following additional methods are available:

       $r = HTTP::Request->new( $method, $uri )
       $r = HTTP::Request->new( $method, $uri, $header )
       $r = HTTP::Request->new( $method, $uri, $header, $content )
	   Constructs a new "HTTP::Request" object describing a request on the object $uri using method $method.  The $method argument must be a
	   string.  The $uri argument can be either a string, or a reference to a "URI" object.  The optional $header argument should be a
	   reference to an "HTTP::Headers" object or a plain array reference of key/value pairs.  The optional $content argument should be a
	   string of bytes.

       $r = HTTP::Request->parse( $str )
	   This constructs a new request object by parsing the given string.

       $r->method
       $r->method( $val )
	   This is used to get/set the method attribute.  The method should be a short string like "GET", "HEAD", "PUT" or "POST".

       $r->uri
       $r->uri( $val )
	   This is used to get/set the uri attribute.  The $val can be a reference to a URI object or a plain string.  If a string is given, then
	   it should be parseable as an absolute URI.

       $r->header( $field )
       $r->header( $field => $value )
	   This is used to get/set header values and it is inherited from "HTTP::Headers" via "HTTP::Message".	See HTTP::Headers for details and
	   other similar methods that can be used to access the headers.

       $r->accept_decodable
	   This will set the "Accept-Encoding" header to the list of encodings that decoded_content() can decode.

       $r->content
       $r->content( $bytes )
	   This is used to get/set the content and it is inherited from the "HTTP::Message" base class.  See HTTP::Message for details and other
	   methods that can be used to access the content.

	   Note that the content should be a string of bytes.  Strings in perl can contain characters outside the range of a byte.  The "Encode"
	   module can be used to turn such strings into a string of bytes.

       $r->as_string
       $r->as_string( $eol )
	   Method returning a textual representation of the request.

SEE ALSO

       HTTP::Headers, HTTP::Message, HTTP::Request::Common, HTTP::Response

COPYRIGHT

       Copyright 1995-2004 Gisle Aas.

       This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.18.2							    2012-02-15							  HTTP::Request(3)