Re: Forward declarations

From	Nick Bowler <nbowler@draconx.ca>
Newsgroups	comp.lang.c
Subject	Re: Forward declarations
Date	2015-11-13 18:20 +0000
Organization	A noiseless patient Spider
Message-ID	<n259ls$b8$4@dont-email.me> (permalink)
References	<868218d9-3441-42d4-8006-7684e9f034fa@googlegroups.com> <n1vjru$45r$1@dont-email.me> <8e0d7ce4-abc9-4134-8c4b-ea3296c939ad@googlegroups.com> <n1vmpb$fi2$2@dont-email.me>

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On Wed, 11 Nov 2015 16:29:55 +0100, David Brown wrote:
> On 11/11/15 16:21, Rick C. Hodgin wrote:
>> I do not propose forward declarations be done away with.  They have
>> their place.  But in many cases they're not, and forcing the
>> requirement means making writing the code harder for people (lots of
>> people, everyone who programs in C) when the compiler could do that
>> job for them, allowing them to have an easier job of authoring source
>> code.
>> 
> 
> Fair enough, I suppose.  But I don't personally think that the
> requirement for forward declarations is at all onerous - when I code, I
> almost never use them (except for defining exported functions and data,
> and we agree that those are fine).  Even if I did have particular reason
> to want to write a static function after its usage rather than before,
> I just can't see it as a big issue.

It's not a big issue.  But it is pointless repetition.  The saving
grace is that compilers generally check the consistency of declarations
within a translation unit (up to substitution of compatible types),
so problems with the duplicate declarations are likely to be noticed
quickly.

I mentioned this example in another thread:

It is currently impossible in C to write mutually recursive
functions without declaring at least one of the functions twice.
Requiring redundant declarations is rather arbitrary and not helpful.

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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