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Re: Beginner....Decimal/Octal converter help

From Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups comp.lang.c
Subject Re: Beginner....Decimal/Octal converter help
Date 2022-09-11 16:12 +0100
Organization A noiseless patient Spider
Message-ID <8735cy0wt4.fsf@bsb.me.uk> (permalink)
References (4 earlier) <875yhv30nu.fsf@bsb.me.uk> <tfi6jk$1f9ct$1@dont-email.me> <87zgf714zc.fsf@bsb.me.uk> <tfil39$1h9u$1@gioia.aioe.org> <tfkj2l$1t7f3$1@dont-email.me>

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David Brown <david.brown@hesbynett.no> writes:

> The "fast" and "least" types /do/ have their uses.  There are not many
> targets that don't support 8-bit char and everything else as a power
> of 8 bits, but there /are/ a few.  The main class of exceptions are
> DSP processors, and some highly specialised task-specific embedded
> processors.  With C23, I believe types (u)int8_t, (u)int16_t,
> (u)int32_t and (u)int64_t have become mandatory - a target that does
> not support these natively must simulate them.  This renders the
> "least" types obsolete.

You are looking at them entirely from the point of view of portability,
but their main use is in explaining what data the program needs.  In the
vast number of cases, writing int_least8_t (say) says exactly what's
needed and using int8_t says something incorrect about the code.

The (u)intN_t types are most commonly needed to match external
structures.  There is very little code that breaks if the type is wider.
The more common exception being cases where N-bit modulo arithmetic is
part of the algorithm, in which case uintN_t describes the precisely.

> The "fast" types, on the other hand, can have real use in embedded
> systems that span a range of target devices.  Some 16-bit, 32-bit and
> 64-bit processors require extra masking or extending instructions when
> dealing with 8-bit or 16-bit data (the original Alpha processor was
> particularly bad).  So local variables of a larger type are more
> efficient.  On the other hand, these will be much less efficient if
> the code is then compiled for an 8-bit target.  The main type of
> interest here is "(u)int_fast8_t", since most uses of "int_fast16_t"
> can be written as "int".

In fact may programmers are, in effect, using the "least" types because
int really means int_least16_t and long means int_least32_t.

-- 
Ben.

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Beginner....Decimal/Octal converter help ManyBeers <markzuffi@yahoo.com> - 2022-09-08 11:34 -0700
  Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-08 11:56 -0700
  Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-08 20:19 +0100
  Re: Beginner....Decimal/Octal converter help Barry Schwarz <schwarzb@delq.com> - 2022-09-08 12:34 -0700
  Re: Beginner....Decimal/Octal converter help Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2022-09-08 20:38 -0600
  Re: Beginner....Decimal/Octal converter help Öö Tiib <ootiib@hot.ee> - 2022-09-09 03:22 -0700
    Re: Beginner....Decimal/Octal converter help gazelle@shell.xmission.com (Kenny McCormack) - 2022-09-09 13:30 +0000
  Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-09 09:16 -0700
    Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-09 19:06 +0000
      Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 11:58 +0200
        Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-10 11:37 +0100
          Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 13:05 +0200
          Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-10 14:42 +0000
            Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-10 16:10 +0100
              Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 18:14 +0200
        Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-10 12:54 +0100
          Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 16:22 +0200
            Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-10 19:03 +0100
              Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-10 19:30 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-10 19:47 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-11 14:07 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-11 16:12 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-11 17:58 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-11 21:14 +0100
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 20:01 -0700
                Re: Beginner....Decimal/Octal converter help Richard Damon <Richard@Damon-Family.org> - 2022-09-11 23:32 -0400
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-12 13:52 +0000
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-14 03:24 -0700
                Re: Beginner....Decimal/Octal converter help Richard Damon <Richard@Damon-Family.org> - 2022-09-14 08:10 -0400
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-26 06:09 -0800
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-12 16:53 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-12 16:48 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-12 17:46 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-12 20:37 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 00:03 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-13 12:31 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-13 12:48 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 14:18 +0100
                Re: Beginner....Decimal/Octal converter help Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-09-13 17:13 +0300
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-13 16:50 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 18:47 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 03:16 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-13 20:15 +0200
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-13 20:29 +0000
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 22:22 +0100
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 14:37 -0700
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 23:16 +0100
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-13 22:16 +0000
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 16:15 -0700
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 16:15 -0700
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-14 10:58 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 15:36 +0100
                Re: Beginner....Decimal/Octal converter help Richard Harnden <richard.nospam@gmail.com> - 2022-09-14 21:53 +0100
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-14 05:55 +0000
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 10:10 +0200
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-14 07:54 -0700
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 18:32 +0200
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-14 18:39 +0100
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-15 01:12 +0000
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-15 09:11 +0200
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-15 08:07 -0700
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-14 18:40 +0000
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-14 05:45 +0000
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 12:11 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 09:57 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 03:09 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 10:29 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 15:14 +0100
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-14 07:36 -0700
                Re: Beginner....Decimal/Octal converter help Öö Tiib <ootiib@hot.ee> - 2022-10-03 01:10 -0700
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-03 11:36 +0100
                Re: Beginner....Decimal/Octal converter help Öö Tiib <ootiib@hot.ee> - 2022-10-04 02:13 -0700
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-04 16:27 +0100
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 11:48 -0700
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 10:38 +0200
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-14 14:27 +0000
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-14 07:58 -0700
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-16 13:06 -0700
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-16 13:16 -0700
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-12 17:55 +0000
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-12 18:22 +0000
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-12 20:41 +0100
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-11 15:45 -0700
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-11 15:41 -0700
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-12 17:06 +0200
              Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 06:46 -0700
          Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 06:57 -0700
      Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 07:07 -0700
        Neologism (Was: Beginner....Decimal/Octal converter help) gazelle@shell.xmission.com (Kenny McCormack) - 2022-09-11 14:18 +0000
        Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-11 16:33 +0000
          Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-13 15:40 -0700
  Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-09 23:08 +0000
    Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 06:37 -0700
      Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-11 16:31 +0000
        Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-13 15:44 -0700

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