[racket] Socket and character resp. block device file

At Sun, 5 Jan 2014 21:45:59 +0100, Manfred Lotz wrote:
> This might be a stupid question. But how do I find out in Racket if a
> file is a socket or a haracter resp. block device file.

I don't think any functions currently provide that information. (The
only related function that comes to mind is `terminal-port?`, and even
that function works on ports instead of files.)