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

From	David Brown <david.brown@hesbynett.no>
Newsgroups	comp.lang.c
Subject	Re: Why _Bool was not defined as enum in C99?
Date	2016-09-16 20:31 +0200
Organization	A noiseless patient Spider
Message-ID	<nrhdqa$sgd$1@dont-email.me> (permalink)
References	(10 earlier) <d96aea8f-52de-4481-bd08-e15819a98181@googlegroups.com> <nrf8em$pi5$1@dont-email.me> <dd046188-15a4-4276-8905-4459d338e08e@googlegroups.com> <nrg8iq$rre$1@dont-email.me> <60b625eb-9e50-434f-9be0-d37b1c2455a9@googlegroups.com>

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On 16/09/16 16:34, supercat@casperkitty.com wrote:
> On Friday, September 16, 2016 at 2:56:22 AM UTC-5, David Brown wrote:
>> OK, I should have written "if a function's return type is not bool, then
>> you already know it is possible that it may yield other values, unless
>> the compiler has the function definition available during compilation of
>> the function's caller, or it knows the exact specification of the
>> function because it is defined in the C standards".
>>
>> Happy now?
>
> Given:
>
>      _Bool x = superRandomFunction(2);
>
> where superRandomFunction is a piece of user-written code that will
> return 0..N-1, how should I tell the compiler it doesn't need to generate
> code to coerce x to the range 0..1?
>

Do it any way you like - try reading your compiler manual for ideas, 
such as:

	int y = superRandomFunction(2);
	if ((y != 0) && (y != 1)) __builtin_unreachable();
	bool x = y;


Or simply accept that it /does/ /not/ /matter/.  Your 
superRandomFunction will take long enough to run that the instructions 
needed to make a valid bool are likely to be negligible.

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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