Re: Forward declarations

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: Forward declarations
Date	2015-11-15 18:53 +0000
Organization	A noiseless patient Spider
Message-ID	<874mgnt7qk.fsf@bsb.me.uk> (permalink)
References	(10 earlier) <97e66a45-03e0-40ea-96fc-0cbeef3b1319@googlegroups.com> <n2a5kh$fr8$1@dont-email.me> <4769f4ec-99fc-4f8d-aa9f-124178189371@googlegroups.com> <87d1vbt8y7.fsf@bsb.me.uk> <n2aji7$a3j$1@dont-email.me>

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BartC <bc@freeuk.com> writes:

> On 15/11/2015 18:26, Ben Bacarisse wrote:
>> "Rick C. Hodgin" <rick.c.hodgin@gmail.com> writes:
>>
>
>>> You can do that in terms of general variable creation, but not in
>>> terms of a function parameter declaration.
>>
>> C does not have function parameters.  The example had a pointer
>> parameter.
>>
>>> In the case of function
>>> parameter declaration, be it in the prototype or the function body,
>>> the declaration is always there, and always provides the declaration,
>>> and, provided the function is called, it is also always defined in
>>> usage (as by the passed value).
>>
>> Nonsense.  In the case of an object, be it in the prototype or the
>> function body, the declaration is always there, and always provides the
>> declaration, and, provided the function is called, it is also always
>> defined in usage (as by the passed value).  You are trying to invent a
>> distinction between function pointers and other kinds of object that is
>> simply not there.
>
> There is a subtle difference. A properly written declaration for a
> function pointer would need to specify the function signature: the
> parameter types and return type.

That's not subtle.  Function pointer declarations are different to other
declarations in significant ways.  They are just not different in the
way that Rick would like then to be.

> But the function signature is already most of the information that
> would be in a forward declaration and that is necessary for the
> function to be correctly called. All that's missing is the name of the
> function.

A pointer to int has even more -- it contains *all* the information for
the int to be used.  All that's missing is the int it points to.

-- 
Ben.

Thread

Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-10 14:20 -0800
  Re: Forward declarations jacobnavia <jacob@jacob.remcomp.fr> - 2015-11-10 23:38 +0100
    Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-10 15:00 -0800
      Re: Forward declarations Ian Collins <ian-news@hotmail.com> - 2015-11-11 12:24 +1300
        Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-10 15:53 -0800
          Re: Forward declarations gazelle@shell.xmission.com (Kenny McCormack) - 2015-11-11 00:01 +0000
          Re: Forward declarations Ian Collins <ian-news@hotmail.com> - 2015-11-11 13:46 +1300
            Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-10 21:05 -0800
    Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-11 00:21 +0000
  Re: Forward declarations Lőrinczy Zsigmond <zsiga@nospam.for.me> - 2015-11-11 10:16 +0100
    Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-11 07:19 -0800
  Re: Forward declarations David Brown <david.brown@hesbynett.no> - 2015-11-11 15:40 +0100
    Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-11 07:21 -0800
      Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-11 07:23 -0800
      Re: Forward declarations David Brown <david.brown@hesbynett.no> - 2015-11-11 16:29 +0100
        Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-11 07:31 -0800
        Re: Forward declarations Nick Bowler <nbowler@draconx.ca> - 2015-11-13 18:20 +0000
          Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-13 10:39 -0800
            Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-13 19:40 +0000
          Re: Forward declarations Tim Rentsch <txr@alumni.caltech.edu> - 2015-11-14 11:42 -0800
            Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-14 12:32 -0800
              Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 00:15 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-14 16:34 -0800
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 01:54 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-14 18:00 -0800
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 02:13 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-14 18:26 -0800
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 02:34 +0000
                Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-15 11:11 +0000
              Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 02:36 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-14 19:25 -0800
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-14 19:37 -0800
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-14 20:11 -0800
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 10:36 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 06:16 -0800
                Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-15 14:44 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 09:41 -0800
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 18:26 +0000
                Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-15 18:42 +0000
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 18:53 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 12:58 -0800
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 12:49 -0800
                Re: Forward declarations Ian Collins <ian-news@hotmail.com> - 2015-11-16 10:01 +1300
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-15 14:54 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 09:53 -0800
                Re: Forward declarations Keith Thompson <kst-u@mib.org> - 2015-11-15 10:36 -0800
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 12:56 -0800
                Re: Forward declarations Ian Collins <ian-news@hotmail.com> - 2015-11-16 10:04 +1300
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 13:11 -0800
                Re: Forward declarations Ian Collins <ian-news@hotmail.com> - 2015-11-16 10:25 +1300
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 13:37 -0800
              Re: Forward declarations Tim Rentsch <txr@alumni.caltech.edu> - 2015-11-15 13:13 -0800
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 13:16 -0800
                Re: Forward declarations David Brown <david.brown@hesbynett.no> - 2015-11-16 00:23 +0100
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 16:20 -0800
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-16 00:47 +0000
                Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-16 01:28 +0000
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-16 01:57 +0000
                Re: Forward declarations Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-11-15 21:15 -0500
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-16 11:05 +0000
                Re: Forward declarations Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-11-16 10:18 -0500
                Re: Forward declarations Richard Heathfield <rjh@cpax.org.uk> - 2015-11-16 06:44 +0000
                Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-16 11:26 +0000
                Re: Forward declarations David Brown <david.brown@hesbynett.no> - 2015-11-16 12:43 +0100
                Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-16 12:20 +0000
                Re: Forward declarations David Brown <david.brown@hesbynett.no> - 2015-11-16 14:38 +0100
                Re: Forward declarations Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-16 13:26 +0000
                Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-16 13:53 +0000
                Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-15 18:12 -0800
      Re: Forward declarations pa@see.signature.invalid (Pierre Asselin) - 2015-11-12 01:54 +0000
        Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-12 02:08 -0800
    Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-12 09:58 +0000
  Re: Forward declarations John Bode <jfbode1029@gmail.com> - 2015-11-17 14:46 -0800
    Re: Forward declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-11-17 14:59 -0800
    Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-17 23:35 +0000
      Re: Forward declarations BartC <bc@freeuk.com> - 2015-11-17 23:40 +0000
        Re: Forward declarations Keith Thompson <kst-u@mib.org> - 2015-11-17 19:48 -0800
      Re: Forward declarations glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-18 01:04 +0000

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