An ASCII string will not work. If you convert 32894 to an ascii string you
will have five bytes, but you need four. In my original post I showed the C
program I used to convert any 32-bit number to 4 bytes.
Feb 2, 2022, 10:16 by python-list@python.org:
> I applaud trying to find the right solution but wonder if a more trivial
> solution is even being considered. It ignores big and little endians and just
> converts your data into another form and back.
>
> If all you want to do is send an integer that fit in 32 bits or 64 bits, why
> not convert it to a character string in a form that both machines will see
> the same way and when read back, convert it back to an integer?
>
> As long as both side see the same string, this can be done in reasonable time
> and portably.
>
> Or am I missing something? Is "1234" not necessarily seen in the same order,
> or "1.234e3" or whatever?
>
> Obviously, if the mechanism is heavily used and multiple sides keep reading
> and even writing the same memory location, this is not ideal. But having
> different incompatible processors looking at the same memory is also not.
>
> -----Original Message-----
> From: Dennis Lee Bieber <wlfr...@ix.netcom.com>
> To: python-list@python.org
> Sent: Wed, Feb 2, 2022 12:30 am
> Subject: Re: Data unchanged when passing data to Python in multiprocessing
> shared memory
>
>
> On Wed, 2 Feb 2022 00:40:22 +0100 (CET), Jen Kris <jenk...@tutanota.com>
>
> declaimed the following:
>
>
>
>>
>>
>> breakup = int.from_bytes(byte_val, "big")
>>
>
> >print("this is breakup " + str(breakup))
>
>>
>>
>
> >Python prints: this is breakup 32894
>
>>
>>
>
> >Note that I had to switch from little endian to big endian. Python is
> >little endian by default, but in this case it's big endian.
>
>>
>>
>
> Look at the struct module. I'm pretty certain it has flags for big or
>
> little end, or system native (that, or run your integers through the
>
> various "network byte order" functions that I think C and Python both
>
> support.
>
>
>
> https://www.gta.ufrj.br/ensino/eel878/sockets/htonsman.html
>
>
>
>
>
> >However, if anyone on this list knows how to pass data from a non-Python
> >language to Python in multiprocessing.shared_memory please let me (and the
> >list) know.
>
>
>
> <pondering>MMU cache lines not writing through to RAM? Can't find
>
> anything on Google to force a cache flush</pondering> Can you test on a
>
> different OS? (Windows vs Linux)
>
>
>
>
>
>
>
> --
>
> Wulfraed Dennis Lee Bieber AF6VN
>
> wlfr...@ix.netcom.com http://wlfraed.microdiversity.freeddns.org/
>
> --
>
> https://mail.python.org/mailman/listinfo/python-list
>
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