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Groups > comp.lang.c > #139435

Re: calling argumentless function with argument

From jt@toerring.de (Jens Thoms Toerring)
Newsgroups comp.lang.c
Subject Re: calling argumentless function with argument
Date 2019-01-05 13:17 +0000
Organization Freie Universitaet Berlin
Message-ID <g9bp36F2osvU1@mid.uni-berlin.de> (permalink)
References <g99egeFi15cU1@mid.uni-berlin.de>

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Hi,

   thank you for the excellent answers! I already had
suspected that there'd be something fishy about this
but couldn't find the relevant sections of the standard.

Concerning the question "what's it possibly good for?":
I'm dealing with an application that has grown over se-
veral years in a somewhat "organical" way;-) It e.g. talks
with energy meters. And when a meter measures a new value
several other subsystems have to be notified. So the module
for the meter contains a number of calls of functions in
those subsystems that may be interested in the fact that a
new measurement is ready (e.g. the accounting subsystem,
the web interface subsystem etc.).

But there are a number of energy meters that have to be
supported, and as they all work quite differently each
has its own module. Now each of these modules contains the
calls to the other subsystems. This involves a lot of code
duplication (not even always done correctly), and then:
why should a module dealing with an enery meter know at
all about all the other subsystems and what they may want
to know?

So we consider moving to a better approach where the meter
just "raises" an event, indicating a new value to be ready,
and the new subsystem for dealing with these events calls a
list of functions that interested subsystems have registered
for this event.

Unfortunately, for historical reasons some of these func-
tions accept a pointer, while others accept no argument.
To minimize the amount of work to implement this and lower
the bar to adopting the new system, it would be helpful if
the existing functions could be used without modifications.
For that being able to call a function that does not accept
arguments with an argument could be quite nice. As it stands
we have to change all these functions to accept an argument
that's ignored anyway, and to hunt down all other calls of
the functions and add a basically useless argument to all
of them.

Of course, this isn't just about energy meters, there
are quite a number of other subsystems where it would be
better if "events" could be raised and then dealt with
by a central instance, distributing the information
to all subsystems that have registered their interest.

                    Best regards, Jens
-- 
  \   Jens Thoms Toerring  ___      jt@toerring.de
   \__________________________      http://toerring.de

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calling argumentless function with argument jt@toerring.de (Jens Thoms Toerring) - 2019-01-04 16:04 +0000
  Re: calling argumentless function with argument David Brown <david.brown@hesbynett.no> - 2019-01-04 17:34 +0100
    Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-04 17:30 +0000
      Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-04 09:50 -0800
        Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 05:58 -0800
          Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 07:56 -0800
            Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 10:56 -0800
              Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 14:55 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 01:29 +0100
                Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 02:20 +0000
                Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-06 02:51 +0000
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 12:12 +0100
                Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 11:53 +0000
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 12:58 +0100
                Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 11:45 +0000
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 12:58 +0100
                Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 12:24 +0000
                Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-06 04:34 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:41 +0100
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 04:10 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:51 +0100
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:56 +0100
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 05:20 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 16:08 +0100
                Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-06 15:59 -0800
                Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 13:42 +0000
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 06:22 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 16:19 +0100
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 07:42 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 08:05 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 08:30 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 17:44 +0100
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 08:54 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 08:02 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 08:07 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 09:16 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 09:40 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 09:57 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-09 02:23 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 16:17 +0100
                Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 16:56 +0000
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 09:12 -0800
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 12:39 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 18:26 +0100
                Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 18:52 +0000
                Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 02:32 -0800
                Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-06 04:38 -0800
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:42 +0100
                Re: calling argumentless function with argument Robert Wessel <robertwessel2@yahoo.com> - 2019-01-06 10:27 -0600
                Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 17:47 +0100
      Re: calling argumentless function with argument David Brown <david.brown@hesbynett.no> - 2019-01-04 19:30 +0100
      Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-04 10:55 -0800
      Re: calling argumentless function with argument Robert Wessel <robertwessel2@yahoo.com> - 2019-01-05 00:16 -0600
    Re: calling argumentless function with argument queequeg@trust.no1 (Queequeg) - 2019-01-07 10:43 +0000
      Re: calling argumentless function with argument Robert Wessel <robertwessel2@yahoo.com> - 2019-01-07 16:25 -0600
  Re: calling argumentless function with argument Barry Schwarz <schwarzb@dqel.com> - 2019-01-04 09:54 -0800
  Re: calling argumentless function with argument Thiago Adams <thiago.adams@gmail.com> - 2019-01-04 10:26 -0800
    Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-04 12:07 -0800
  Re: calling argumentless function with argument James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-04 15:03 -0500
    Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-05 00:04 +0000
      Re: calling argumentless function with argument James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-05 22:36 -0500
  Re: calling argumentless function with argument jt@toerring.de (Jens Thoms Toerring) - 2019-01-05 13:17 +0000
    Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 06:06 -0800
    Re: calling argumentless function with argument David Brown <david.brown@hesbynett.no> - 2019-01-05 15:42 +0100
      Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-05 14:58 +0000
    Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-05 16:11 +0100
    Re: calling argumentless function with argument Richard Damon <Richard@Damon-Family.org> - 2019-01-05 11:23 -0500
      Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-05 16:53 +0000
        Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-06 00:46 +0000

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