I noticed a while ago that CURLOPT_RETURNTRANSFER added trailing null chars to the end of html pages, which seemed odd, but didn't seem like a bug.  Then I noticed that on binary files, in fact what it does is REPLACE the trailing char with a null char.

Oddly, setting CURLOPT_HEADER to 1 seems to fix the problem.

<?
		$f = fopen('/tmp/bla1','w');
		$ch = curl_init();
		curl_setopt($ch, CURLOPT_URL,"http://www.php.net/gifs/small_submit.gif");
		curl_setopt($ch, CURLOPT_FILE,$f);
		curl_exec($ch);
		curl_close($ch);
		rewind($f);
		fclose($f);

		$ch = curl_init();
		curl_setopt($ch, CURLOPT_URL,"http://www.php.net/gifs/small_submit.gif");
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
		$ret = curl_exec($ch);
		curl_close($ch);

		$f = fopen('/tmp/bla2','w');
		$ret = fwrite($f,$ret,strlen($ret));
		fclose($f);
		
		system('diff /tmp/bla2 /tmp/bla1');
?>