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Groups > comp.lang.c > #62253

Re: determines if it is a signed type

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: determines if it is a signed type
Date 2015-05-18 15:21 -0700
Organization None to speak of
Message-ID <87k2w54je5.fsf@kst-u.example.com> (permalink)
References (2 earlier) <mjbtjr$db3$1@dont-email.me> <87mw12qqk7.fsf@kst-u.example.com> <mjcnfm$43l$1@dont-email.me> <87a8x253s1.fsf@kst-u.example.com> <mjdero$674$1@dont-email.me>

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Richard Heathfield <rjh@cpax.org.uk> writes:
> On 18/05/15 16:00, Keith Thompson wrote:
[...]
>> The best we can do is this:
>>
>> #include <stdio.h>
>> #include <time.h>
>> #include <stdint.h>
>
> Sorry, I thought you said "portably"? If you #include <stdint.h>, you
> immediately lose portability to older C implementations.
>
> I realise that this is a price you have decided you are prepared to
> pay, but not everyone is in that position.

I did not consider implementations that don't support the current
or previous C standard.  Nor did I consider implementations that
only support K&R C, or B, or BCPL.

I could have covered C90 by checking __STD_VERSION__ and falling
back to long and unsigned long rather than intmax_t and uintmax_t.
On the other hand, some pre-C99 implementations support long long as
an extension; I suppose you could check whether LLONG_MAX is defined
in <limits.h> On the other other hand, a pre-C99 implementation is
unlikely to use a type wider than long for time_t.

As far as I know, the most prominent implementation that doesn't
have at least reasonable support for C99 is Microsoft's, and I
believe it does support <stdint.h>.  The situation for embedded
systems may be different.

-- 
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

determines if it is a signed type asetofsymbols@gmail.com - 2015-05-17 10:07 -0700
  Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-17 18:12 +0100
    Re: determines if it is a signed type asetofsymbols@gmail.com - 2015-05-17 10:34 -0700
      Re: determines if it is a signed type asetofsymbols@gmail.com - 2015-05-17 11:09 -0700
      Re: determines if it is a signed type Kusalananda <kusalananda@example.com> - 2015-05-17 18:22 +0000
        Re: determines if it is a signed type asetofsymbols@gmail.com - 2015-05-17 11:31 -0700
          Re: determines if it is a signed type Kusalananda <kusalananda@example.com> - 2015-05-17 19:59 +0000
  Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-17 13:12 -0700
  Re: determines if it is a signed type Morris Dovey <mrdovey@iedu.com> - 2015-05-17 19:08 -0500
    Re: determines if it is a signed type Morris Dovey <mrdovey@iedu.com> - 2015-05-17 19:46 -0500
    Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-18 01:59 +0100
      Re: determines if it is a signed type Morris Dovey <mrdovey@iedu.com> - 2015-05-17 20:10 -0500
      Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-18 00:37 -0700
        Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-18 21:15 +0100
          Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-18 15:15 -0700
        Re: determines if it is a signed type glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-18 21:51 +0000
          Re: determines if it is a signed type James Kuyper <jameskuyper@verizon.net> - 2015-05-18 18:00 -0400
      Re: determines if it is a signed type glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-18 14:37 +0000
        Re: determines if it is a signed type jacobnavia <jacob@jacob.remcomp.fr> - 2015-05-18 17:09 +0200
          Re: determines if it is a signed type glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-18 18:14 +0000
    Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-18 06:34 +0100
      Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-18 00:43 -0700
        Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-18 13:56 +0100
          Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-18 08:00 -0700
            Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-18 20:35 +0100
              Re: determines if it is a signed type jacobnavia <jacob@jacob.remcomp.fr> - 2015-05-18 23:08 +0200
                Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-18 22:32 +0100
                Re: determines if it is a signed type jacobnavia <jacob@jacob.remcomp.fr> - 2015-05-19 00:44 +0200
                Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-19 00:05 +0100
                Re: determines if it is a signed type jacobnavia <jacob@jacob.remcomp.fr> - 2015-05-19 01:43 +0200
                Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-19 01:08 +0100
                Re: determines if it is a signed type "Bartc" <bartc@freeuk.com> - 2015-05-19 11:33 +0100
                Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-19 08:15 -0700
                Re: determines if it is a signed type "Bartc" <bartc@freeuk.com> - 2015-05-19 19:36 +0100
                Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-19 11:55 -0700
                Re: determines if it is a signed type jacobnavia <jacob@jacob.remcomp.fr> - 2015-05-19 11:39 +0200
                Re: determines if it is a signed type "Bartc" <bartc@freeuk.com> - 2015-05-19 11:44 +0100
                Re: determines if it is a signed type jacobnavia <jacob@jacob.remcomp.fr> - 2015-05-19 12:11 +0200
                Re: determines if it is a signed type jadill33@gmail.com - 2015-05-19 05:45 -0700
                Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-19 15:03 +0100
                Re: determines if it is a signed type jadill33@gmail.com - 2015-05-19 08:46 -0700
                Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-19 17:08 +0100
                Re: determines if it is a signed type jadill33@gmail.com - 2015-05-19 09:52 -0700
                Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-19 20:36 +0100
                Re: determines if it is a signed type jadill33@gmail.com - 2015-05-20 07:40 -0700
                Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-20 23:12 +0100
                Re: determines if it is a signed type jadill33@gmail.com - 2015-05-21 13:52 -0700
                Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-21 22:48 +0100
                Re: determines if it is a signed type jadill33@gmail.com - 2015-05-22 05:50 -0700
                Re: determines if it is a signed type Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-05-22 23:14 +0100
                Re: determines if it is a signed type jadill33@gmail.com - 2015-05-26 14:31 -0700
                Re: determines if it is a signed type Tim Rentsch <txr@alumni.caltech.edu> - 2015-05-22 23:32 -0700
                Re: determines if it is a signed type David Brown <david.brown@hesbynett.no> - 2015-05-20 12:26 +0200
                Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-19 15:28 +0100
                Re: determines if it is a signed type raltbos@xs4all.nl (Richard Bos) - 2015-05-23 10:37 +0000
              Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-18 15:21 -0700
                Re: determines if it is a signed type Richard Heathfield <rjh@cpax.org.uk> - 2015-05-19 00:04 +0100
                Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-19 08:03 -0700
                Re: determines if it is a signed type David Brown <david.brown@hesbynett.no> - 2015-05-19 08:47 +0200
                Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-19 08:07 -0700
          Re: determines if it is a signed type James Kuyper <jameskuyper@verizon.net> - 2015-05-18 11:28 -0400
    Re: determines if it is a signed type Keith Thompson <kst-u@mib.org> - 2015-05-18 00:40 -0700

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