fopen and fwrite help??

So, I've gotten a script on one subdomain of mine to write (append) to a file on another subdomain of mine (even though is_writable said I couldn't do it)...

This is all well and good, and it will serve, but it's not perfect

I'm using this script to add contents to the file, each one timestamped.



The problem thing I'd like to improve is that I'd like to sort the items in descending date order (newest items first).

if ($postresults == 'yes') { // add the result to a file
		$filename = '/path/to/file.txt';
		
		// because I'm opening $filename in append mode,
		// the file pointer is at the bottom of the file hence
		// that's where $posttext will go when we fwrite() it.
		if (!$handle = fopen($filename, 'a')) {
			echo "Cannot open file ($filename).";
			break;
		}
		
		// Write $posttext to our opened file.
		if (fwrite($handle, $posttext) === FALSE) {
			echo "Cannot write to file ($filename).";
			break;
		}
		
		echo "Success, wrote ($posttext) to file ($filename)";
		
		fclose($handle);
	}

The file already has some static content which will not change at the top of the file.



I'm guessing I'd need to use fseek(), but fseek warns me that if I open the file in append mode ("a" or "a+"), then it will be written at the end of the file regardless.

Any help?