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Groups > comp.std.c > #6236

Re: bit-fields of type unsigned long and unsigned long long

From Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups comp.std.c
Subject Re: bit-fields of type unsigned long and unsigned long long
Date 2021-06-23 10:53 -0700
Organization A noiseless patient Spider
Message-ID <86fsx8bh88.fsf@linuxsc.com> (permalink)
References <sastag$a33$1@solani.org>

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Philipp Klaus Krause <pkk@spth.de> writes:

> Since bit-fields of type unsigned long and unsigned long long are
> useful, commonly suppoted by implementations, and commonly used, I'd
> like to see the standard support them.
>
> Here's  a draft of a proposal for that:
>
> http://www.colecovision.eu/stuff/proposal-unsigned-long-bit-field.html

Here is a possible (and simpler) alternative.

Type specifier for bit-fields is _Bool, int, signed, or unsigned
(with signed int and unsigned int being synonymous with signed
and unsigned, respectively).

Bit-fields of type _Bool act just like they do now.

Bit-fields of type int are either the same as an unsigned
bit-field or the same as a signed bit-field, with the choice
being implementation-defined, just like they are now.

Bit-fields of types signed and unsigned may use widths up to the
widths of intmax_t and uintmax_t, respectively.

The type of a signed bit-field is the first of signed, long,
long long, and intmax_t, that is wide enough to hold all the
possible values of the bit-field.

The type of an unsigned bit-field is the first of unsigned,
unsigned long, unsigned long long, and uintmax_t, that is wide
enough to hold all the possible values of the bit-field.

For compatibility with current integer promotion rules, an access
for an unsigned bit-field whose range of possible values are all
representable within the range of signed int yields a value that
has been promoted to type signed int, just like such things are
done now.  In all other cases the type of a bit-field access
is the type of the bit-field, as stated above.

(Personally I like this approach better than allowing different
integer types as bit-field specifiers.)

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Thread

bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-22 16:49 +0200
  Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-22 17:18 +0200
    Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-22 11:17 -0700
      Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-23 08:25 +0200
        Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-23 08:59 +0200
          Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-23 13:12 +0200
            Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-23 14:14 +0200
              Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-23 17:45 +0200
                Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-23 10:22 -0700
                Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-23 19:52 +0200
                Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-23 16:12 -0700
                Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-24 10:41 +0200
                Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-24 10:32 +0200
        Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-23 00:39 -0700
  Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-23 13:22 +0200
    Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-23 18:27 +0200
  Re: bit-fields of type unsigned long and unsigned long long Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-06-23 10:53 -0700
    Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-23 20:13 +0200
      Re: bit-fields of type unsigned long and unsigned long long Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-06-24 11:48 -0700
        Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-24 12:23 -0700
          Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-24 22:40 +0200
          Re: bit-fields of type unsigned long and unsigned long long Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-10 09:13 -0700
        Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-24 22:14 +0200
          Re: bit-fields of type unsigned long and unsigned long long Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-10 09:23 -0700
    Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-24 11:02 +0200
      Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-24 11:06 -0700
        Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-24 23:11 +0200
          Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-24 15:16 -0700
            Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-25 10:43 +0200
              Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-25 02:02 -0700
                Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-25 13:54 +0200
                Re: bit-fields of type unsigned long and unsigned long long Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-06-25 13:07 +0100
                Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-25 15:17 +0200
                Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-25 08:22 -0700
                Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-25 18:22 +0200
                Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-25 13:28 -0700
                Re: bit-fields of type unsigned long and unsigned long long Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-06-25 19:12 +0100
                Re: bit-fields of type unsigned long and unsigned long long Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-10 08:58 -0700
                Re: bit-fields of type unsigned long and unsigned long long Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-25 08:09 -0700
              Re: bit-fields of type unsigned long and unsigned long long Philipp Klaus Krause <pkk@spth.de> - 2021-06-25 14:43 +0200
                Re: bit-fields of type unsigned long and unsigned long long David Brown <david.brown@hesbynett.no> - 2021-06-25 15:33 +0200
                Re: bit-fields of type unsigned long and unsigned long long Jakob Bohm <jb-usenet@wisemo.com.invalid> - 2021-07-06 23:18 +0200

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