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Groups > comp.lang.c > #92031

Re: sizeof Data types

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: sizeof Data types
Date 2016-08-09 11:35 -0700
Organization None to speak of
Message-ID <lnwpjpu6x3.fsf@kst-u.example.com> (permalink)
References <no34bv$1rus$1@gioia.aioe.org> <nod25d$sp3$1@dont-email.me>

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Ken Brody <kenbrody@spamcop.net> writes:
> On 8/5/2016 6:45 PM, Real Troll wrote:
>>
>> Does this look right for various basic data types:
>>
>>> Storage size for char : 1
>>> Storage size for signed char : 1
>>> Storage size for unsigned char : 1
>>> Storage size for int : 4
>>> Storage size for unsigned int : 4
>>> Storage size for float : 4
>>> Storage size for double : 8
>>> Storage size for short : 2
>>> Storage size for unsigned short : 2
>>> Storage size for long : 4
>>> Storage size for unsigned long : 4
>
> As noted elsethread, except for the three "char" variants, which must be 1, 
> the others can be virtually anything.  (The only restrictions are that some 
> must be "at least" as large as something else -- such as "long" must be "at 
> least" as big as "int".)

As discussed previously, the standard imposes requirements on
the ranges, not the sizes.  For example, the range of int must
be at least -32767..+32767, the range of long must be at least
-2147483647..+2147483647, and the range of int must be a subrange
of the range of long.  In the presence of an implausibly perverse
number of padding bits, sizeof (int) *could* exceed sizeof (long)
(by which I mean only that such an implementation would not violate
the standard).

> Note that, as far as C is concerned, all of the above could be "1".
> (Given a sufficiently large CHAR_BITS.)

Yes (except that it's CHAR_BIT).

> The numbers you see above are probably typical for a 32-bit system.

-- 
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

sizeof Data types Real Troll <real.troll@trolls.com> - 2016-08-05 18:45 -0400
  sizeof Data types jameskuyper@verizon.net - 2016-08-05 17:10 -0700
  Re: sizeof Data types raltbos@xs4all.nl (Richard Bos) - 2016-08-06 10:35 +0000
  Re: sizeof Data types raltbos@xs4all.nl (Richard Bos) - 2016-08-06 10:36 +0000
  Re: sizeof Data types Jean-Marc Bourguet <jm@bourguet.org> - 2016-08-06 22:29 +0200
    Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-09 12:55 -0400
  Re: sizeof Data types BartC <bc@freeuk.com> - 2016-08-06 21:43 +0100
    Re: sizeof Data types jameskuyper@verizon.net - 2016-08-06 15:25 -0700
      Re: sizeof Data types David Brown <david.brown@hesbynett.no> - 2016-08-08 09:48 +0200
        Re: sizeof Data types James Kuyper <jameskuyper@verizon.net> - 2016-08-08 11:05 -0400
          Re: sizeof Data types David Brown <david.brown@hesbynett.no> - 2016-08-08 17:57 +0200
        Re: sizeof Data types supercat@casperkitty.com - 2016-08-08 08:36 -0700
          Re: sizeof Data types David Brown <david.brown@hesbynett.no> - 2016-08-08 19:05 +0200
            Re: sizeof Data types supercat@casperkitty.com - 2016-08-08 14:09 -0700
              Re: sizeof Data types David Brown <david.brown@hesbynett.no> - 2016-08-09 09:38 +0200
                Re: sizeof Data types Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-09 11:23 +0100
                Re: sizeof Data types Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-12 07:42 -0700
                Re: sizeof Data types Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-12 21:38 +0100
                Re: sizeof Data types Keith Thompson <kst-u@mib.org> - 2016-08-09 08:12 -0700
                Re: sizeof Data types supercat@casperkitty.com - 2016-08-10 10:36 -0700
                Re: sizeof Data types Keith Thompson <kst-u@mib.org> - 2016-08-10 11:42 -0700
      Re: sizeof Data types Philip Lantz <prl@canterey.us> - 2016-08-11 10:20 -0700
        Re: sizeof Data types Keith Thompson <kst-u@mib.org> - 2016-08-11 12:04 -0700
        Re: sizeof Data types Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-12 08:22 -0700
    Re: sizeof Data types Nobody <nobody@nowhere.invalid> - 2016-08-07 01:32 +0100
      Re: sizeof Data types Keith Thompson <kst-u@mib.org> - 2016-08-06 18:10 -0700
  Re: sizeof Data types Siri Cruise <chine.bleu@yahoo.com> - 2016-08-06 20:22 -0700
    Re: sizeof Data types Ian Collins <ian-news@hotmail.com> - 2016-08-07 15:40 +1200
    Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-09 13:06 -0400
      Re: sizeof Data types Siri Cruise <chine.bleu@yahoo.com> - 2016-08-09 12:37 -0700
        Re: sizeof Data types Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-11 09:18 -0700
          Re: sizeof Data types Siri Cruise <chine.bleu@yahoo.com> - 2016-08-11 11:11 -0700
            Re: sizeof Data types Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-08-11 12:26 -0600
              Re: sizeof Data types David Brown <david.brown@hesbynett.no> - 2016-08-11 23:31 +0200
                Re: sizeof Data types supercat@casperkitty.com - 2016-08-11 14:59 -0700
              Re: sizeof Data types Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-12 00:15 -0700
            Re: sizeof Data types Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-12 08:05 -0700
  Re: sizeof Data types John Bode <jfbode1029@gmail.com> - 2016-08-08 12:38 -0700
    Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-09 13:08 -0400
      Re: sizeof Data types Keith Thompson <kst-u@mib.org> - 2016-08-09 10:43 -0700
      Re: sizeof Data types "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-09 13:41 -0400
        Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-10 11:51 -0400
          Re: sizeof Data types "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-10 12:35 -0400
            Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-11 11:53 -0400
              Re: sizeof Data types "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-13 11:29 -0400
                Re: sizeof Data types supercat@casperkitty.com - 2016-08-13 09:18 -0700
          Re: sizeof Data types Keith Thompson <kst-u@mib.org> - 2016-08-10 10:13 -0700
            Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-11 11:56 -0400
  Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-09 12:59 -0400
    Re: sizeof Data types "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-09 13:49 -0400
      Re: sizeof Data types Ken Brody <kenbrody@spamcop.net> - 2016-08-10 12:08 -0400
    Re: sizeof Data types Keith Thompson <kst-u@mib.org> - 2016-08-09 11:35 -0700

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