[Python-ideas] Add create mode to open()

M.-A. Lemburg mal at egenix.com
Wed Aug 17 11:52:03 CEST 2011

Antoine Pitrou wrote:
> On Wed, 17 Aug 2011 14:11:32 +1000
> Nick Coghlan <ncoghlan at gmail.com> wrote:
>> On Wed, Aug 17, 2011 at 1:43 PM, Devin Jeanpierre
>> <jeanpierreda at gmail.com> wrote:
>>> I'd also point out that for those that don't want race conditions,
>>> Python is discouraging. The correct incantation involves two
>>> undocumented constants, plus a unique and rarely used way of opening
>>> files that involves unix file descriptors.
>> FWIW, when you control the filename, you can include an additional
>> subdirectory precisely for the exception when a second process
>> attempts to create the same subdirectory.
> How do you create a directory and a file atomically?

On Windows, directories are created atomically. On Unix,
too, but symlinks are faster. You can use those to implement
cooperative file locks in a fairly cross-platform way.

See e.g. mx.Misc.FileLock in

Marc-Andre Lemburg

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