Re: Why _Bool was not defined as enum in C99?

From	Tim Rentsch <txr@alumni.caltech.edu>
Newsgroups	comp.lang.c
Subject	Re: Why _Bool was not defined as enum in C99?
Date	2016-09-16 08:06 -0700
Organization	A noiseless patient Spider
Message-ID	<kfn37kzhojo.fsf@x-alumni2.alumni.caltech.edu> (permalink)
References	(6 earlier) <2a43ea82-8927-435f-9897-096948ddbc15@googlegroups.com> <e3ul6kF1l4bU2@mid.individual.net> <nrdu54$2ii$1@dont-email.me> <kfnsht1gg2n.fsf@x-alumni2.alumni.caltech.edu> <nrg9tf$vqr$1@dont-email.me>

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David Brown <david.brown@hesbynett.no> writes:

> On 15/09/16 20:42, Tim Rentsch wrote:
>> David Brown <david.brown@hesbynett.no> writes:
>>
>>> [...]
>>>
>>> And it is usually not hard to write code that is valid C, and valid C++,
>>> and not /too/ strange for either language.  [...]
>>
>> I disagree.  This can be true for small examples or certain
>> limited contexts, but it is not true for any significant
>> body of code.
>
> Code like this will often look strange for C++ code, but that is
> primarily because you are not using common features of C++ code
> (classes, namespaces, templates, etc.), rather than because you are
> using the common C/C++ subset in a strange way.  But IME it will seldom
> look very strange when viewed as C code.
>
> However, you don't normally have to write a lot of code that can be
> compiled as C and C++ - usually it is restricted to headers.

My comment was meant in the context of writing .c files, not only
function headers.  If all one is writing is function prototypes
then it is pretty easy to write code in the intersection of C and
C++.  My comment though was meant more generally, since what the
OP is asking about encompasses source code at the .c level, not
only headers.

> I have had occasion to write code for customers which they wanted to be
> both C and C++ compatible - it was not a difficult requirement, and it
> did not lead to unusual or idiosyncratic code.

It is possible to write C code that is also C++ code in much the
same way that it is possible to write English prose that doesn't
have any "j"'s in it.  It may even look perfectly ordinary -
consider as an example my last paragraph.  However it is extra
effort to do so:  while writing this paragraph I had to go back
and change two occurrences of "just" to "only" so there wouldn't
be any "j"'s.  And the result of that change is that it reads
(IMO) a little worse than the original.  There is an analogous
effect with code in the C/C++ intersection, except there I think
it's worse than simply leaving out "j"'s in English.

> To be fair, when I have written such code, it has been in small (or
> "resource constrained") embedded systems.  For example, casting void*
> pointers before assignment was not an issue - they are very rare in such
> code.  malloc() and friends are typically banned anyway.

I imagine there were other consequences as well, but I won't
ask about those since it's tangential to the area I mean
to address.

>> (I note that the original message went on to some particular
>> details, and those comments refine the general statement
>> above.  I'm not offering any comments on the details, and
>> may agree (or not) on some of those.  But as a general
>> blanket statement IMO the statement above is just wrong.)
>
> Can you give an example (obviously a short one) of code written in
> "C/C++" that you think would be particularly strange or unusual when
> viewed as C code?

I wrote a short example (which I will describe but not post) of a
way to do runtime polymorphism for this very thread.  After I had
written it I realized it wasn't suitable for the OP's needs (or
at least what were thought to be needs) because my C code would
not compile as C++.  The .h file, that was no problem.  The .c
file, blammo!  Roughly 30% of the lines had incompatibilities.
These fell into three categories:  void *, compound literals, and
designated initializers.  (It's possible there were other
problems but those are the ones I remember.)  Now of course it
is possible to work around all of these, but it's a big pain in
the you-know-where.  For me it is simply above threshold, like
trying to write in C90 again - it isn't that I can't do it, but
it's not natural, and certainly isn't merely a minor adjustment.

By the way, I tried to write the text new in this posting
without any "j"'s, but one crept in there right at the end
in "adjustment" (and after I had already changed a "just" to
"merely"... oh well).  :)

Thread

Why _Bool was not defined as enum in C99? thiago.adams@gmail.com - 2016-09-12 13:24 -0700
  Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-12 21:56 +0100
    Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-12 15:59 -0700
    Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-13 16:05 -0700
      Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-13 18:17 -0700
        Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-14 01:20 +0100
        Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-14 03:59 -0700
        Re: Why _Bool was not defined as enum in C99? Nobody <nobody@nowhere.invalid> - 2016-09-14 17:31 +0100
          Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 09:49 -0700
            Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 11:45 -0700
        Re: Why _Bool was not defined as enum in C99? <william@wilbur.25thandClement.com> - 2016-09-14 14:13 -0700
          Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 16:26 -0700
  Re: Why _Bool was not defined as enum in C99? "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-12 17:11 -0400
  Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-13 15:55 -0700
    Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-13 18:08 -0700
      Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-14 03:56 -0700
        Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 07:58 -0700
          Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-14 19:39 +0100
            Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 13:52 -0700
              Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-15 00:53 +0100
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 17:04 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 20:52 -0700
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 19:26 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 19:04 -0700
            Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 14:21 -0700
              Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 16:23 -0700
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 17:06 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 20:45 -0700
                Re: Why _Bool was not defined as enum in C99? Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-14 22:12 -0400
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-15 12:37 +0200
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 09:35 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 00:47 +0200
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 22:02 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 09:56 +0200
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-16 07:34 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 20:31 +0200
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-16 12:32 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-17 23:30 +0200
                Re: Why _Bool was not defined as enum in C99? BartC <bc@freeuk.com> - 2016-09-15 18:25 +0100
                Re: Why _Bool was not defined as enum in C99? luser droog <luser.droog@gmail.com> - 2016-09-15 12:35 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 00:51 +0200
                Re: Why _Bool was not defined as enum in C99? luser droog <luser.droog@gmail.com> - 2016-09-16 17:02 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 19:23 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-17 23:35 +0200
        Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 10:40 -0700
          Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 10:01 -0700
            Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 11:35 -0700
              Re: Why _Bool was not defined as enum in C99? Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-14 22:15 -0400
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 23:51 -0700
                Re: Why _Bool was not defined as enum in C99? Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-15 15:14 -0400
              Re: Why _Bool was not defined as enum in C99? Ian Collins <ian-news@hotmail.com> - 2016-09-15 16:08 +1200
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-15 12:46 +0200
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 09:37 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 00:53 +0200
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 21:45 -0700
                Re: Why _Bool was not defined as enum in C99? Richard Heathfield <rjh@cpax.org.uk> - 2016-09-16 06:32 +0100
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 09:59 +0200
                Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-16 11:00 +0100
                Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 04:46 -0700
                Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-16 12:58 +0100
                Re: Why _Bool was not defined as enum in C99? Melzzzzz <Melzzzzz@zzzzz.com> - 2016-09-16 12:06 +0000
                Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 05:13 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 10:47 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 10:46 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 10:02 +0200
                Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-15 11:42 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 10:19 +0200
                Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-16 08:06 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 20:51 +0200
                Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 11:56 -0700
                Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-22 22:38 -0700
          Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-14 11:42 -0700
            Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 14:02 -0700
              Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-15 10:51 -0700
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 11:18 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-15 13:46 -0700
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 13:10 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-15 16:01 -0700
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-15 13:40 -0700
                Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-16 07:21 -0700
                Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 07:37 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 20:55 +0200
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 14:43 -0700
                Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-16 15:36 -0700
                Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-17 23:45 +0200
                Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-17 17:14 -0700

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