easy way to determine if a stream or fd is seekable

[perryh at pluto.rain.com]

Alexander Best <arundel at freebsd.org> wrote:

> here's a revised patch.
> ...
> +.Sh CAVEATS
> +If the
> +.Fn lseek
> +system call is operating on a device, which is incapable of seeking,
> +it will request the seek operation and complete successfully.

I think it would be better without the first comma (after "device").

IMO the whole section should be added to BUGS rather than creating
a new CAVEATS section.  Returning "success" when the requested
operation actually _failed_ is a serious POLA violation.