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Groups > comp.lang.c > #123677

Re: Some kind of contextual modulo operator?

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: Some kind of contextual modulo operator?
Date 2017-12-01 08:56 -0800
Organization None to speak of
Message-ID <lnbmjixu7r.fsf@kst-u.example.com> (permalink)
References (4 earlier) <c73af526-10fe-46c3-a98b-ec3345ec9238@googlegroups.com> <DiHTB.65770$7d.19343@fx05.am4> <1679454a-2d88-4821-be92-a73dba4d4d75@googlegroups.com> <jFSTB.60693$1M.45530@fx32.am4> <bfeUB.110929$au1.21996@fx45.am4>

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bartc <bc@freeuk.com> writes:
[...]
> A further point about malloc: I generally call it as a foreign function, 
> with its parameter defined as either a 32-bit or 64-bit signed integer.
>
> Not that I ever intend to pass it negative values, but that I don't 
> expect to pass parameters which are 2**31 or above, or 2**63 or above.
>
> On Windows, in 32-bit mode on x86, I don't think you can make a single 
> allocation above 2**31 (and the limit is reduced further by the fact 
> that some of the 2GB virtual address space is already occupied by the 
> running program and any previous allocations).
>
> While in 64-bit mode, a single allocation of some 9 billion GB would be 
> unlikely to succeed.
>
> So you wouldn't lose much by not using 'size_t' in these cases.

If you use a 32-bit signed integer, then (a) you lose the ability to
allocate 2GB or more (which I just did successfully on a small test
program), and (b) if you're calling it as a foreign function and you get
the size of the argument wrong, the call might not work at all.

I understand that calling malloc() as a foreign function is more
complicated than calling it from C.  I don't understand why you'd
deliberately use a signed argument for a function that takes an unsigned
argument.

-- 
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

Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-29 10:41 -0800
  Re: Some kind of contextual modulo operator? jameskuyper@verizon.net - 2017-11-29 11:12 -0800
    Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-11-29 19:22 +0000
      Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-11-29 19:43 +0000
        Re: Some kind of contextual modulo operator? jameskuyper@verizon.net - 2017-11-29 12:33 -0800
          Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-11-29 23:22 +0000
            Re: Some kind of contextual modulo operator? jameskuyper@verizon.net - 2017-11-29 20:53 -0800
              Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-11-30 12:17 +0000
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-01 15:08 +0000
                Re: Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-12-01 07:31 -0800
                Re: Some kind of contextual modulo operator? scott@slp53.sl.home (Scott Lurndal) - 2017-12-01 16:32 +0000
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-01 17:07 +0000
                Re: Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-12-01 09:15 -0800
                Re: Some kind of contextual modulo operator? scott@slp53.sl.home (Scott Lurndal) - 2017-12-01 18:14 +0000
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-01 19:03 +0000
                Re: Some kind of contextual modulo operator? scott@slp53.sl.home (Scott Lurndal) - 2017-12-01 20:54 +0000
                Re: Some kind of contextual modulo operator? Keith Thompson <kst-u@mib.org> - 2017-12-01 12:09 -0800
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-01 21:56 +0000
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-01 23:11 +0000
                Re: Some kind of contextual modulo operator? supercat@casperkitty.com - 2017-12-01 15:16 -0800
                Re: Some kind of contextual modulo operator? David Brown <david.brown@hesbynett.no> - 2017-12-02 17:09 +0100
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-02 19:42 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-03 09:16 +1300
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-02 22:06 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-03 11:20 +1300
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-03 00:01 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-03 13:55 +1300
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-03 02:14 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-03 16:13 +1300
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-03 12:28 +0000
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-03 14:26 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-04 10:49 +1300
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-04 10:38 +1300
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-03 23:00 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-04 12:10 +1300
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-03 23:33 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-04 13:18 +1300
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-04 12:19 +0000
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-05 07:58 +1300
                Re: Some kind of contextual modulo operator? David Brown <david.brown@hesbynett.no> - 2017-12-04 00:30 +0100
                Packed structs (was Re: Some kind of contextual modulo operator?) scott@slp53.sl.home (Scott Lurndal) - 2017-12-04 15:02 +0000
                Re: Packed structs (was Re: Some kind of contextual modulo operator?) David Brown <david.brown@hesbynett.no> - 2017-12-04 16:34 +0100
                Re: Packed structs (was Re: Some kind of contextual modulo operator?) Keith Thompson <kst-u@mib.org> - 2017-12-04 09:23 -0800
                Re: Packed structs (was Re: Some kind of contextual modulo operator?) scott@slp53.sl.home (Scott Lurndal) - 2017-12-04 18:31 +0000
                Re: Packed structs (was Re: Some kind of contextual modulo operator?) supercat@casperkitty.com - 2017-12-04 15:37 -0800
                Re: Some kind of contextual modulo operator? supercat@casperkitty.com - 2017-12-04 08:39 -0800
                Re: Some kind of contextual modulo operator? "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2017-12-03 18:13 -0800
                Re: Some kind of contextual modulo operator? Ian Collins <ian-news@hotmail.com> - 2017-12-03 14:50 +1300
                Re: Some kind of contextual modulo operator? scott@slp53.sl.home (Scott Lurndal) - 2017-12-04 15:00 +0000
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-04 15:53 +0000
                Re: Some kind of contextual modulo operator? scott@slp53.sl.home (Scott Lurndal) - 2017-12-04 18:26 +0000
                Re: Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-12-04 10:34 -0800
                Re: Some kind of contextual modulo operator? David Brown <david.brown@hesbynett.no> - 2017-12-03 19:40 +0100
                Re: Some kind of contextual modulo operator? David Kleinecke <dkleinecke@gmail.com> - 2017-12-03 11:35 -0800
                Re: Some kind of contextual modulo operator? scott@slp53.sl.home (Scott Lurndal) - 2017-12-04 14:59 +0000
                Re: Some kind of contextual modulo operator? Keith Thompson <kst-u@mib.org> - 2017-12-01 08:56 -0800
                Re: Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-12-01 08:58 -0800
                Re: Some kind of contextual modulo operator? scott@slp53.sl.home (Scott Lurndal) - 2017-12-01 18:16 +0000
                Re: Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-12-01 10:28 -0800
                Re: Some kind of contextual modulo operator? David Brown <david.brown@hesbynett.no> - 2017-12-01 20:19 +0100
                Re: Some kind of contextual modulo operator? Gareth Owen <gwowen@gmail.com> - 2017-12-01 22:22 +0000
                Re: Some kind of contextual modulo operator? jameskuyper@verizon.net - 2017-12-01 07:49 -0800
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-01 16:54 +0000
                Re: Some kind of contextual modulo operator? jameskuyper@verizon.net - 2017-12-01 09:34 -0800
                Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-12-01 18:48 +0000
                Re: Some kind of contextual modulo operator? jameskuyper@verizon.net - 2017-12-01 11:27 -0800
      Re: Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-29 12:17 -0800
        Re: Some kind of contextual modulo operator? bartc <bc@freeuk.com> - 2017-11-30 12:27 +0000
          Re: Some kind of contextual modulo operator? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-30 06:11 -0800
    Re: Some kind of contextual modulo operator? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-11-29 15:02 -0500
  Some kind of contextual modulo operator? mcheung63@gmail.com - 2017-12-08 23:20 -0800

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