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Groups > comp.lang.c > #120667

Re: const and the C type system

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: const and the C type system
Date 2017-10-01 14:09 -0700
Organization None to speak of
Message-ID <lno9pqshgg.fsf@kst-u.example.com> (permalink)
References (5 earlier) <fKQzB.1787364$DB.699792@fx04.am4> <oqqik3$gr9$1@dont-email.me> <zR5AB.929642$284.420422@fx20.am4> <oqrk6s$ao6$1@dont-email.me> <gFcAB.1102930$LJ4.573616@fx37.am4>

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bartc <bc@freeuk.com> writes:
> On 01/10/2017 21:46, David Brown wrote:
>> On 01/10/17 15:13, bartc wrote:
[...]
>>> Why didn't you define c and e in terms of a+b and d*c? 
>> 
>> Because it is not allowed in C? Isn't that a good enough reason?
>
> Are you sure? This seemed to work fine with gcc:
>
>   static const int a = 100;
>   static const double b = 200.1;
>   static const double c = a+b;
>   static const long long int d = 5000000000;
>   static const double e = d*c;
>   static const unsigned long long f = 0xffffffffffffffff;
>
> (And yes gcc did tell me about the overflow.)

On my system (Ubuntu 17.04, gcc 6.3.0, x86_64):

    $ cat c.c
    static const int a = 100;
    static const double b = 200.1;
    static const double c = a+b;
    static const long long int d = 5000000000;
    static const double e = d*c;
    static const unsigned long long f = 0xffffffffffffffff;
    $ gcc -c c.c
    c.c:3:25: error: initializer element is not constant
     static const double c = a+b;
                             ^
    c.c:5:25: error: initializer element is not constant
     static const double e = d*c;
                             ^
    $ 

I get the same error messages if the declarations are at block scope.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Thread

const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-28 19:51 -0700
  Re: const and the C type system Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-09-28 21:32 -0600
    Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 05:45 -0700
      Re: const and the C type system bartc <bc@freeuk.com> - 2017-09-29 14:05 +0100
        Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 06:17 -0700
    Re: const and the C type system asetofsymbols@gmail.com - 2017-10-01 22:35 -0700
  Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-09-29 10:59 +0200
    Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 06:06 -0700
      Re: const and the C type system bartc <bc@freeuk.com> - 2017-09-29 14:24 +0100
        Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 06:52 -0700
          Re: const and the C type system jameskuyper@verizon.net - 2017-09-29 09:17 -0700
            Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 10:50 -0700
              Re: const and the C type system jameskuyper@verizon.net - 2017-09-29 11:06 -0700
                Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 11:27 -0700
          Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-30 13:13 -0700
            Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-30 13:31 -0700
        Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-09-29 09:10 -0700
          Re: const and the C type system bartc <bc@freeuk.com> - 2017-09-29 18:33 +0100
          Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 11:10 -0700
        Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-09-30 08:29 +1300
        Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-09-30 18:48 +0200
          Re: const and the C type system bartc <bc@freeuk.com> - 2017-09-30 18:44 +0100
            Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-10-01 09:12 +1300
              Re: const and the C type system bartc <bc@freeuk.com> - 2017-09-30 21:50 +0100
                Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-10-01 10:10 +1300
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-09-30 23:17 +0100
                Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-10-01 11:38 +1300
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 00:44 +0100
                Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-10-01 14:33 +1300
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 10:42 +0100
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 19:58 +0200
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 21:30 +0100
                Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-10-02 17:48 +1300
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-02 11:14 +0100
                Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-10-02 23:22 +1300
                Re: const and the C type system Richard Damon <Richard@Damon-Family.org> - 2017-10-01 13:58 -0400
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 18:20 +0200
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 18:41 +0100
                Re: const and the C type system supercat@casperkitty.com - 2017-10-01 12:03 -0700
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 23:05 +0200
                Re: const and the C type system supercat@casperkitty.com - 2017-10-01 15:58 -0700
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-02 09:56 +0200
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-02 00:24 +0100
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-02 12:20 +0200
                Re: const and the C type system Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-10-02 06:03 -0700
                Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-10-02 06:34 -0700
                Re: const and the C type system supercat@casperkitty.com - 2017-10-02 23:38 -0700
                Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-10-01 13:03 -0700
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 23:12 +0200
                Re: const and the C type system supercat@casperkitty.com - 2017-10-01 11:12 -0700
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 13:48 +0200
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 14:13 +0100
                Re: const and the C type system supercat <flatfinger@casperkitty.com> - 2017-10-01 10:32 -0700
              Re: const and the C type system supercat@casperkitty.com - 2017-09-30 13:52 -0700
            Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-09-30 13:35 -0700
              Re: const and the C type system bartc <bc@freeuk.com> - 2017-09-30 21:58 +0100
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 12:03 +0100
              Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-30 14:00 -0700
                Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-09-30 15:33 -0700
                Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-10-01 12:45 -0700
            Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 13:13 +0200
              Re: const and the C type system Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-10-01 05:22 -0700
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 20:06 +0200
                Re: const and the C type system supercat@casperkitty.com - 2017-10-01 12:16 -0700
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 21:01 +0100
                Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-10-01 13:21 -0700
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 21:50 +0100
                Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-10-02 05:35 -0700
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-02 14:01 +0100
                Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-10-02 06:29 -0700
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-02 15:19 +0100
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 23:19 +0200
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 22:33 +0100
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-02 00:10 +0200
              Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 14:13 +0100
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-01 22:46 +0200
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 21:57 +0100
                Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-10-01 14:09 -0700
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-01 23:54 +0100
                Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-10-01 19:12 -0700
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-02 11:36 +0100
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-02 12:45 +0200
                Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-10-02 09:40 -0700
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-02 19:33 +0100
                Re: const and the C type system scott@slp53.sl.home (Scott Lurndal) - 2017-10-02 19:09 +0000
                Re: const and the C type system Ian Collins <ian-news@hotmail.com> - 2017-10-03 08:12 +1300
                Re: const and the C type system bartc <bc@freeuk.com> - 2017-10-02 20:30 +0100
                Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-10-02 12:37 -0700
                Re: const and the C type system jadill33@gmail.com - 2017-10-02 12:49 -0700
                Re: const and the C type system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-10-06 20:47 +0000
                Re: const and the C type system Keith Thompson <kst-u@mib.org> - 2017-10-06 15:41 -0700
                Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-10-02 12:42 +0200
              Re: const and the C type system Gareth Owen <gwowen@gmail.com> - 2017-10-01 21:18 +0100
          Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-30 12:22 -0700
      Re: const and the C type system David Brown <david.brown@hesbynett.no> - 2017-09-30 18:44 +0200
    Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 07:01 -0700
      Re: const and the C type system Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-29 20:18 +0100
        Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-09-29 12:40 -0700
          Re: const and the C type system Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-29 21:28 +0100
  Re: const and the C type system fir <profesor.fir@gmail.com> - 2017-09-29 08:21 -0700
    Re: const and the C type system fir <profesor.fir@gmail.com> - 2017-09-29 08:38 -0700
  Re: const and the C type system John Bode <jfbode1029@gmail.com> - 2017-10-02 09:20 -0700
    Re: const and the C type system Thiago Adams <thiago.adams@gmail.com> - 2017-10-02 09:53 -0700
    Re: const and the C type system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-10-09 13:27 +0000

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