[python-win32] Opening existing memory mapped files with pywin32

[Eryk Sun]

On 2/16/21, Tim Roberts <timr at probo.com> wrote:
> Eryk Sun wrote:
>>
>> I'm sorry to say that the only reliable solution is to directly call
>> WinAPI OpenFileMappingW() and MapViewOfFile() using a foreign-function
>> interface (FFI) package such as ctypes or CFFI. I can write up an
>> example if you need help.
>
> Respectfully, I think you have misread the original message.  He is a
> relative beginner, just trying to do a simple file mapping. Based on his
> description, mmap should be able to do what he needs.

Sorry, I'm sure you're right, now that I think about it. I was
responding reflexively based on the OP's code that attempts to
create/open a file mapping with a name and 0 maximum size (i.e.
unknown size; just map it all and query the size), since I've
previously seen people trying and failing to do that with mmap in
various IPC cases. The GUID name didn't help to clarify matters, since
it's just as likely to be generated as a unique object name in the
current session. I also think at unconscious level I didn't want to
assume a confused misreading of the documented function parameters.

Anyway, maybe the discussion will help someone else that's searching
for information on the topic.