Make a unique filesystem path, without creating the file

[Jon Ribbens]

On 2016-02-25, Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:
> The links already provided go through the evidence. For example, they 
> explain that /dev/random and /dev/urandom both use the exact same CSPRNG. If 
> you don't believe that, you can actually read the source to Linux, FreeBSD, 
> OpenBSD and NetBSD. (But not OS X, sorry.)

Actually yes OS X:

http://www.opensource.apple.com/source/xnu/xnu-3248.20.55/bsd/dev/random/
http://www.opensource.apple.com/source/xnu/xnu-3248.20.55/osfmk/prng/