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Groups > comp.lang.c > #384079

Re: Casting the return value of ...

From Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups comp.lang.c
Subject Re: Casting the return value of ...
Date 2024-03-28 22:02 -0700
Organization None to speak of
Message-ID <87r0ftsk9g.fsf@nosuchdomain.example.com> (permalink)
References <uu416t$33u55$1@news.xmission.com> <uu5gpa$3mm6$1@dont-email.me>

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Andrey Tarasevich <andreytarasevich@hotmail.com> writes:
[...]
> No, it isn't even remotely the same. C language allows implicit casts
> from any object pointer type to `void *` and vice-versa. Which is why 
> casting the result of `malloc` is unnecessary.

To be picky, there are no "implicit casts".  There are implicit
conversions.  A cast is an explicit conversion.

> C language does not support implicit casts between object pointer
> types (like `void *`) and function pointer types. Moreover, C language
> still does not support _explicit_ casts between `void *` and function
> pointer types either. POSIX guarantees/requirements are not C.

It "does not support" them in the sense that it does not define their
behavior.  Such a cast does not violate any constraint, and an
implementation or third-party standard is free to define the semantics.

By contrast, conversions between floating types and pointer types are
constraint violations.

[...]

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Medtronic
void Void(void) { Void(); } /* The recursive call of the void */

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Thread

Casting the return value of ... gazelle@shell.xmission.com (Kenny McCormack) - 2024-03-28 15:09 +0000
  Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 18:16 +0000
    Re: Casting the return value of ... scott@slp53.sl.home (Scott Lurndal) - 2024-03-28 18:53 +0000
      Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-30 10:33 -0700
        Re: Casting the return value of ... scott@slp53.sl.home (Scott Lurndal) - 2024-03-30 19:29 +0000
          Re: Casting the return value of ... Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-30 23:05 +0000
            Re: Casting the return value of ... scott@slp53.sl.home (Scott Lurndal) - 2024-03-30 23:25 +0000
            Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-31 15:44 +0200
            Re: Casting the return value of ... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-31 13:15 -0700
          Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-08 23:01 -0700
            Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-04-09 10:03 +0200
    Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 12:38 -0700
      Re: Casting the return value of ... bart <bc@freeuk.com> - 2024-03-28 20:30 +0000
        Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 14:07 -0700
          Re: Casting the return value of ... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-28 14:15 -0700
          Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 21:44 +0000
            Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 22:01 +0000
              Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 22:33 +0000
                Re: Casting the return value of ... Michael S <already5chosen@yahoo.com> - 2024-03-29 15:53 +0200
                gcc Bugzilla search (was: Casting the return value of ...) Michael S <already5chosen@yahoo.com> - 2024-03-29 16:01 +0200
                Re: gcc Bugzilla search David Brown <david.brown@hesbynett.no> - 2024-03-29 17:00 +0100
            Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 15:37 -0700
            Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-07 21:23 -0700
          Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-29 14:06 +0100
            Re: Casting the return value of ... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-29 15:46 -0700
        Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-29 13:58 +0100
          Re: Casting the return value of ... bart <bc@freeuk.com> - 2024-03-29 13:32 +0000
            Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-29 17:10 +0100
            Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-30 02:32 -0700
              Re: Casting the return value of ... bart <bc@freeuk.com> - 2024-03-30 11:14 +0000
                Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-08 23:41 -0700
  Re: Casting the return value of ... Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-03-28 21:41 -0700
    Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 22:02 -0700
  Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-29 15:52 -0700

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