Extending domain of O_TMPFILE?

[Mark Geisert]

Hi folks,
I've been following up on a response I made to a Cygwin user in
https://cygwin.com/pipermail/cygwin/2021-January/247306.html .
I've figured out that Cygwin's implementation of the open() flag O_TMPFILE 
follows Linux in that one can't specify the name of a file when using this 
flag.  User supplies only the path, and Cygwin chooses an obscure file 
name for you.

That means the OP's suggested improvement of applying O_TMPFILE semantics 
to files created by tmpfile() won't work.

Could we consider expanding the domain of O_TMPFILE so that the user can 
supply a name for the temporary file rather than just the path to its 
directory?  I've been playing around with proof-of-concept code but I want 
to make sure this is acceptable before submitting implementation patches.

This would be a Cygwin-specific enhancement to a Linux-specific feature. 
I haven't checked yet if the BSDs have O_TMPFILE in any form.
Thanks for any feedback!

..mark