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Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3
From: |
Arne Babenhauserheide |
Subject: |
Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3 |
Date: |
Sat, 08 Jun 2019 11:46:10 +0200 |
User-agent: |
mu4e 1.2.0; emacs 26.1 |
Chris Vine <address@hidden> writes:
> On Sat, 08 Jun 2019 10:07:45 +0200
> Arne Babenhauserheide <address@hidden> wrote:
> [snip]
>> Wow, I didn’t know that you could do that.
>>
>> However: "The details of that allocation are implementation-defined, and
>> it's undefined behavior to read from the member of the union that wasn't
>> most recently written." https://en.cppreference.com/w/cpp/language/union
>>
>> Can you guarantee that this works?
>
> This is C and not C++ and the provision to which you refer does not
> apply.
>
> Reading from a member of a union other than the one last written to is
> implementation defined in C89/90, and defined in C99 (with Technical
> Corrigendum 3) and above
Thank you for the correction and explanation!
Best wishes,
Arne
--
Unpolitisch sein
heißt politisch sein
ohne es zu merken
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- Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3, (continued)
Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3, Mark H Weaver, 2019/06/07