Is os.replace() atomic on Windows?

Question

In the docs it says that replacing files are guaranteed to be atomic on POSIX systems. Does this mean that it's not atomic on Windows?

The docs actually say "If successful, the renaming will be an atomic operation", and then in parenthesis "((this is a POSIX requirement)". So it reads, to me at least, like the operation on all OSes is atomic if successful, and the POSIX thing perhaps added motivation for this. — kabanus, Aug 15 '18 at 16:00
Relevant dialogue from Python bug tracker: https://bugs.python.org/issue27886 — , Aug 15 '18 at 16:04

score 4 · Accepted Answer · edited Jul 20 '19 at 11:45

4

As visible in this thread the atomic replace functionality for windows has been added for version 3.3.

The patch is visible here.

In the background MoveFileEx with when nessesary the MOVEFILE_REPLACE_EXISTING flag added is called.

MoveFileEx is the same method as the openjdk calls. I can't find any documentation stating it is atomic, but the community seems to rely on it.

edited Jul 20 '19 at 11:45

mhsmith

answered Mar 08 '19 at 15:03

NtFreX

1 Answers1