Re: [PATCH] libc_r bug: successful close(2) sets errno to ENOTTY

From: "Jacques A. Vidrine" <nectar_at_FreeBSD.org>
> The application is broken.  You must only check errno if you get an
> error indication from the library call.

errno is only meaningful after a syscall error.

it is also well known that stdio uses isatty(3) (or equivelant) that may
set errno to ENOTTY.