On 8/16/22 09:25, Eli Zaretskii wrote:
> why does this work differently on
> different platforms?

Platforms that lack clock_gettime and CLOCK_MONOTONIC fall back on a 
deterministic algorithm. Presumably MS-DOS one of the few such 
platforms, which is why the problem is observed only on MS-DOS.

How about something like the attached patch to Gnulib's lib/tempname.c? 
If I understand things correctly this should make the names random 
enough on MS-DOS, though Emacs itself still needs a patch as I mentioned 
a few minutes ago.

If this patch isn't good enough for MS-DOS, what sort of random bits are 
easily available on that platform? We don't need anything 
cryptographically secure; a higher-res clock should suffice.