Re: how cast works?

From	Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups	comp.lang.c
Subject	Re: how cast works?
Date	2024-08-12 10:04 -0700
Organization	A noiseless patient Spider
Message-ID	<86frr965bi.fsf@linuxsc.com> (permalink)
References	(7 earlier) <86ttfqin3x.fsf@linuxsc.com> <v9bmqu$2v3e1$1@dont-email.me> <86a5hih0nv.fsf@linuxsc.com> <87h6bqe4x8.fsf@nosuchdomain.example.com> <87mslhag4b.fsf@bsb.me.uk>

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Ben Bacarisse <ben@bsb.me.uk> writes:

> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>
>> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>> [...]
>>
>>> Furthermore, there are cases where having to do a conversion from
>>> one type to the same type has semantic consequences, even though
>>> the types are the same.
>>
>> What are these cases?
>
> The case that comes to mind is where the result of a floating point
> expression is represented with more precision than the type can hold
> when stored.

Right.

> 6.3.1.8 p2:
>   The values of floating operands and of the results of floating
>   expressions may be represented in greater range and precision than
>   that required by the type;  the types are not changed thereby.[63]
>
> The footnote explains that the implicit conversion done on assignment
> will change the value even though the types may be the same:
>
> [63] The cast and assignment operators are still required to remove
>      extra range and precision.

A related item is that the rule for 'return' is not the same as
assignment.  When returning a value from a function, the value
of the return expression is converted to the return type of the
function, /unless/ the type of the return expression is the same
as the return type of the function, in which case no conversion
takes place (and so extra range and precision may be retained).

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how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-07 08:28 -0300
  Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-07 08:33 -0300
    Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-07 13:13 -0700
    Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 17:43 -0700
      Re: how cast works? Vir Campestris <vir.campestris@invalid.invalid> - 2024-08-12 11:51 +0100
        Challenge/exercise problem - signum() function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-12 08:17 -0700
          Re: Challenge/exercise problem - signum() function Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2024-08-12 16:07 +0000
            Re: Challenge/exercise problem - signum() function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-12 09:57 -0700
  Re: how cast works? Dan Purgert <dan@djph.net> - 2024-08-07 20:00 +0000
    Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-07 13:26 -0700
    Re: how cast works? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-08-07 23:00 +0000
    Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-08 08:14 -0300
      Re: how cast works? Bart <bc@freeuk.com> - 2024-08-08 14:23 +0100
        Re: how cast works? Michael S <already5chosen@yahoo.com> - 2024-08-08 19:32 +0300
          Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-08 14:11 -0300
          Re: how cast works? Bart <bc@freeuk.com> - 2024-08-08 18:29 +0100
            Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-08 14:50 -0300
              Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-08 14:57 -0300
              Re: how cast works? Bart <bc@freeuk.com> - 2024-08-08 19:01 +0100
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-08 15:13 -0300
              Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-08 12:29 -0700
            Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-08 19:58 +0200
              Re: how cast works? Bart <bc@freeuk.com> - 2024-08-08 20:09 +0100
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 00:32 +0200
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-08 16:14 -0700
                Re: how cast works? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-08-09 02:47 +0000
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-08 22:55 -0700
                Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-09 02:08 -0400
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 18:16 +0200
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 12:18 -0700
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 17:07 -0700
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-11 20:14 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-09 01:56 +0100
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 19:08 +0200
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-10 11:03 +0100
                Re: how cast works? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-08-09 02:45 +0000
      Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-08 12:42 -0700
        Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-08 17:34 -0300
          Re: how cast works? Bart <bc@freeuk.com> - 2024-08-08 22:41 +0100
            Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-08 16:17 -0700
              Re: how cast works? Bart <bc@freeuk.com> - 2024-08-09 11:04 +0100
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 19:12 +0200
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-12 15:36 +0100
                Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-09 13:57 -0400
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-09 21:59 +0100
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 14:47 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-10 00:32 +0100
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 17:12 -0700
                Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-09 18:29 -0400
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-13 11:18 +0200
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-13 11:34 +0100
                Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-13 07:51 -0400
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-13 14:01 +0100
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-13 12:46 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-13 21:51 +0100
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-13 16:46 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-14 00:56 +0100
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-18 03:37 -0700
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 14:29 -0700
                Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-09 18:35 -0400
                Re: how cast works? Kaz Kylheku <643-408-1753@kylheku.com> - 2024-08-09 21:30 +0000
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 14:57 -0700
                Re: how cast works? Kaz Kylheku <643-408-1753@kylheku.com> - 2024-08-09 23:14 +0000
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 16:58 -0700
                Re: how cast works? Kaz Kylheku <643-408-1753@kylheku.com> - 2024-08-10 00:06 +0000
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 17:27 -0700
                Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-09 20:31 -0400
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-10 01:11 +0100
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-13 11:23 +0200
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 17:32 -0700
                Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-09 18:35 -0400
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 17:27 -0700
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 12:23 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-09 21:31 +0100
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 13:49 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-09 22:01 +0100
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-12 00:33 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-12 12:21 +0100
              Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 17:46 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-12 02:00 +0100
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-11 20:23 -0700
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 20:37 -0700
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-11 21:33 -0700
                Re: how cast works? Ben Bacarisse <ben@bsb.me.uk> - 2024-08-12 16:57 +0100
                Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-12 10:04 -0700
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-12 13:35 -0700
            Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-09 07:57 -0300
              Re: how cast works? Bart <bc@freeuk.com> - 2024-08-09 16:25 +0100
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 12:06 -0700
              Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 19:20 +0200
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-09 15:54 -0300
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-09 16:05 -0300
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 21:43 +0200
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 13:28 -0700
                Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 22:01 +0200
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-10 11:17 +0100
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-10 10:15 -0300
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-10 17:14 +0100
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-10 20:01 -0300
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-10 17:10 -0700
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-11 09:23 -0300
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-11 13:30 +0100
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-11 14:16 -0300
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-11 13:38 -0700
                Re: how cast works? Bart <bc@freeuk.com> - 2024-08-12 12:24 +0100
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 13:26 -0700
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-09 18:01 -0300
                Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 14:53 -0700
              Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-09 12:03 -0700
                Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-09 16:22 -0300
          Re: how cast works? David Brown <david.brown@hesbynett.no> - 2024-08-09 00:36 +0200
    Re: how cast works? Dan Purgert <dan@djph.net> - 2024-08-08 14:08 +0000
    Re: how cast works? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-08-09 02:42 +0000
  Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-07 13:08 -0700
    Re: how cast works? Thiago Adams <thiago.adams@gmail.com> - 2024-08-08 08:35 -0300
      Re: how cast works? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-08-08 12:39 -0700
      Re: how cast works? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-08-08 18:40 -0400
        Re: how cast works? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 17:15 -0700
    Is there an audio book version (Was: how cast works?) gazelle@shell.xmission.com (Kenny McCormack) - 2024-08-08 16:19 +0000
  Re: how cast works? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-08-07 23:03 +0000

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