how to detect if headers have been sent

[sysadmin42]

I have a simple redirect script that helps me save some typing and also gives some nice added functionality for popping around various areas of my site:

function redirect($url,$clear=false) {

	if (!$clear) { //if clear is true, then it will skip the session vars and all.
		//check for session first
		if ($_SESSION['redirect']!='') $url=$_SESSION['redirect'];
		
		//url request supercedes session var
		//use this for special overrides- allows for universal return pages
		if ($_REQUEST['redirect']!='') $url=$_REQUEST['redirect'];
	}
	
	//replace special chars so that you get less errors
	$url=str_replace('-','=',str_replace('+','&',$url));
	
	unset($_SESSION['redirect']);  // clear
	
	if (substr($url,0,1)!="?") $url="?".$url;
	
	//header("Location: $url");
	echo "<script>window.location=\"$url\";</script>";
}

The thing is, sometimes this will be called before page headers are sent and sometimes after. If I use the header("location: $url") after headers then I get the error- headers have already been sent.

I want this script to be generic. In the past, I've simply added another variable in the function, but I want to do away with this variable and auto-detect:

function redirect($url,$clear=false,$js=false) {
...
   if (!$js) use header redirect
   else use javascript redirect
...
}

Do you know of a way to automatically detect whether headers have been sent or not?

"Computer illiterate is a dirty word."

 

[jpadie]

if(headers_sent()){
 //do something
}

 

[sysadmin42]

was that all? i did a whole bunch of googling on this one! Well, thanks!

"Computer illiterate is a dirty word."