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Re: Empty functions (was: GCC and const-correctness)

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Wouter Verhelst <w@uter.be> writes:
> On 11/10/18 17:19, Stefan Ram wrote:
>> Spiros Bousbouras <spibou@gmail.com> writes:
>>> By the way , if I were a compiler writer I would offer a warning for a
>>> function with no code and also offer some way to disable such warnings.
>> 
>>   When it comes to empty functions, we should not forget that
>>   another reasonable reason for an empty function can be seen
>>   in a situation where one can pass in a function as a
>>   /callback/ to a call for something to be done, say at a
>>   certain point. When you want /nothing/ to be done at that
>>   point, you would pass in an /empty function/ (albeit with
>>   the correct type) into that call. Such an empty function is
>>   not a placeholder to be filled in later, but it is intended
>>   to stay empty.
>
> In most such cases, you can pass in NULL as the callback, which then has
> the same effect. In fact, I would say that code which does not act that
> way is buggy, and should be fixed.

A null pointer (which doesn't point to a function) is not the same
as a function that does nothing.  A function that takes a pointer
to a callback function should document what it does with it.  In my
opinion it's perfectly reasonable to require the passed pointer to
be non-null (or perhaps for a null pointer to have some distinct
meaning).

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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GCC and const-correctness Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-10-11 12:17 +0300
  Re: GCC and const-correctness Philipp Klaus Krause <pkk@spth.de> - 2018-10-11 11:22 +0200
    Re: GCC and const-correctness Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-10-11 13:17 +0300
  Re: GCC and const-correctness Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 02:40 -0700
  Re: GCC and const-correctness Spiros Bousbouras <spibou@gmail.com> - 2018-10-11 10:17 +0000
    Re: GCC and const-correctness Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-10-11 13:28 +0300
      Re: GCC and const-correctness Spiros Bousbouras <spibou@gmail.com> - 2018-10-11 10:58 +0000
        Re: GCC and const-correctness jameskuyper@alumni.caltech.edu - 2018-10-11 08:21 -0700
    Re: GCC and const-correctness David Brown <david.brown@hesbynett.no> - 2018-10-11 12:39 +0200
    Re: GCC and const-correctness Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-11 15:02 +0000
      Re: GCC and const-correctness Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-10-11 18:06 +0300
      Re: GCC and const-correctness Wouter Verhelst <w@uter.be> - 2018-10-11 17:23 +0200
        Re: GCC and const-correctness Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-12 10:16 +0000
          Re: GCC and const-correctness David Brown <david.brown@hesbynett.no> - 2018-10-12 13:21 +0200
            Re: GCC and const-correctness Wouter Verhelst <w@uter.be> - 2018-10-13 09:33 +0200
              Re: GCC and const-correctness David Brown <david.brown@hesbynett.no> - 2018-10-13 13:11 +0200
    Re: Empty functions (was: GCC and const-correctness) Wouter Verhelst <w@uter.be> - 2018-10-11 17:25 +0200
      Re: Empty functions (was: GCC and const-correctness) Keith Thompson <kst-u@mib.org> - 2018-10-11 09:23 -0700
        Re: Empty functions (was: GCC and const-correctness) Keith Thompson <kst-u@mib.org> - 2018-10-11 10:54 -0700
        Re: Empty functions (was: GCC and const-correctness) Wouter Verhelst <w@uter.be> - 2018-10-11 19:56 +0200
          Re: Empty functions David Brown <david.brown@hesbynett.no> - 2018-10-11 20:19 +0200
          Re: Empty functions (was: GCC and const-correctness) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-12 02:43 -0700
    Re: Empty functions (was: GCC and const-correctness) Anton Shepelev <ant0n.txt@gmai1.c0m> - 2018-10-11 19:16 +0300

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