Here are somefunctions I found in the code archives to do it. Don't ask me how to use them because I don't know. :-)
http://www.blitzbasic.com/codearcs/codearcs.php?code=390
http://www.blitzbasic.com/codearcs/codearcs.php?code=931
http://www.blitzbasic.com/codearcs/codearcs.php?code=390
http://www.blitzbasic.com/codearcs/codearcs.php?code=931