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Groups > comp.lang.c > #120464

Re: Set the result of void function

From Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups comp.lang.c
Subject Re: Set the result of void function
Date 2017-09-28 18:50 +0100
Organization A noiseless patient Spider
Message-ID <87zi9eg1bb.fsf@bsb.me.uk> (permalink)
References (16 earlier) <ueUyB.1549783$WI6.1384739@fx30.am4> <oqi94p$jl4$1@dont-email.me> <ej6zB.1196081$ik4.742321@fx38.am4> <oqj43k$g9l$1@dont-email.me> <uB9zB.1550017$WI6.973316@fx30.am4>

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bartc <bc@freeuk.com> writes:
<snip>
> OK, I understand. If I write this:
>
> int main(void) {
>   int a;
>   void fn();
>
>   fn(100);
>   fn(200.0);
>   fn("Hello, World!");
>   fn(&a);
> }
>
> which is clearly not right,

That's a bit vague.  It's not a complete program for one thing, but I
don't think there is a way to complete it without it being undefined by
C.  However, one of the C's strengths is the ability to exploit
undefined behaviour in useful ways, some of whohc might make that code
"right" (for the practical programmer).

For example, what you describe here as "clearly not right" is how I
might test an assembler routine with the external name "fn".  Sure, it's
UB (as far as C in concerned) but the implementation may guarantee that
I can link this translation unit with one written in some other language
that defines "fn".

This is not to say you don't have a point, just that your example does
not make it particularly well.  Had you included a definition of fn of
just said that it's undefined by C's definition it would have been clear
that your are pointing out how C compilers sometimes miss opportunities
to report errors.

<snip>
-- 
Ben.

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Thread

Set the result of void function Thiago Adams <thiago.adams@gmail.com> - 2017-09-19 14:23 -0700
  Re: Set the result of void function Thiago Adams <thiago.adams@gmail.com> - 2017-09-19 14:38 -0700
    Re: Set the result of void function gordonb.tfand@burditt.org (Gordon Burditt) - 2017-09-19 17:16 -0500
    Re: Set the result of void function "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-09-20 00:39 +0200
      Re: Set the result of void function James Kuyper <jameskuyper@verizon.net> - 2017-09-19 22:06 -0400
        Re: Set the result of void function "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-09-20 06:51 +0200
          Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-20 10:55 +0100
            Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-20 12:11 +0100
            Re: Set the result of void function fir <profesor.fir@gmail.com> - 2017-09-20 07:17 -0700
          Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-20 11:28 +0100
          Re: Set the result of void function mark.bluemel@gmail.com - 2017-09-20 03:30 -0700
            Re: Set the result of void function fir <profesor.fir@gmail.com> - 2017-09-20 06:53 -0700
              Re: Set the result of void function Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-09-21 03:50 -0500
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-21 11:00 +0100
                Re: Set the result of void function scott@slp53.sl.home (Scott Lurndal) - 2017-09-21 12:39 +0000
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-21 14:12 +0100
                Re: Set the result of void function scott@slp53.sl.home (Scott Lurndal) - 2017-09-21 13:51 +0000
                Re: Set the result of void function Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-09-21 08:36 -0600
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-21 17:51 +0100
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-21 10:06 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-22 08:51 +0200
                Plunging innocent people into poverty (Was: Set the result of void function) gazelle@shell.xmission.com (Kenny McCormack) - 2017-09-23 09:31 +0000
                Re: Plunging innocent people into poverty (Was: Set the result of void function) David Brown <david.brown@hesbynett.no> - 2017-09-23 12:09 +0200
                Re: Plunging innocent people into poverty (Was: Set the result of void function) gazelle@shell.xmission.com (Kenny McCormack) - 2017-09-23 10:25 +0000
                Re: Plunging innocent people into poverty Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2017-09-23 10:43 -0600
                Re: Plunging innocent people into poverty supercat@casperkitty.com - 2017-09-23 10:41 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-22 09:37 +0200
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-22 11:27 +0100
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-22 14:42 +0200
                Re: Set the result of void function Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-09-24 12:09 +0000
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-25 08:31 +0200
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-25 03:52 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-25 13:25 +0200
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-25 04:58 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-25 14:20 +0200
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-25 13:44 +0100
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-25 15:09 +0200
                Re: Set the result of void function Thiago Adams <thiago.adams@gmail.com> - 2017-09-25 05:44 -0700
                Re: Set the result of void function Thiago Adams <thiago.adams@gmail.com> - 2017-09-25 05:58 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-25 15:15 +0200
                Re: Set the result of void function Thiago Adams <thiago.adams@gmail.com> - 2017-09-25 06:46 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-25 16:01 +0200
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-25 07:18 -0700
                Re: Set the result of void function Thiago Adams <thiago.adams@gmail.com> - 2017-09-25 07:55 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-25 08:49 -0700
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-25 09:21 -0700
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-25 09:51 -0700
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-25 21:57 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-25 15:03 -0700
                Re: Set the result of void function Öö Tiib <ootiib@hot.ee> - 2017-09-25 21:34 -0700
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-26 04:28 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-27 08:26 +0200
                Re: Set the result of void function "James R. Kuyper" <jameskuyper@verizon.net> - 2017-09-27 11:48 -0400
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 08:54 +0200
                Re: Set the result of void function gordonb.iddsu@burditt.org (Gordon Burditt) - 2017-09-28 23:33 -0500
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-27 09:15 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-27 17:50 +0100
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-27 10:35 -0700
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-27 18:47 +0100
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-27 10:52 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-27 11:10 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 09:10 +0200
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-27 11:06 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-27 20:01 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-27 12:26 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-27 20:38 +0100
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-27 13:00 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-27 21:54 +0100
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-27 14:12 -0700
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-27 14:34 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-27 23:16 +0100
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-27 16:09 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 01:12 +0100
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-28 02:03 +0100
                Re: Set the result of void function Ian Collins <ian-news@hotmail.com> - 2017-09-28 17:31 +1300
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 09:55 +0200
                Re: Set the result of void function Ian Collins <ian-news@hotmail.com> - 2017-09-28 21:00 +1300
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 10:48 +0100
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 13:20 +0200
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-28 11:29 +0100
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-27 20:27 -0700
                Re: Set the result of void function Gareth Owen <gwowen@gmail.com> - 2017-09-29 19:30 +0100
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-29 19:45 +0100
                Re: Set the result of void function Jerry Stuckle <jstucklex@attglobal.net> - 2017-09-29 14:49 -0400
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-27 15:07 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 09:42 +0200
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 13:55 +0100
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 17:22 +0200
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 09:14 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 20:13 +0200
                Re: Set the result of void function Gareth Owen <gwowen@gmail.com> - 2017-09-29 19:42 +0100
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-28 09:14 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 09:25 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 20:17 +0200
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 17:39 +0100
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-28 10:10 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 19:05 +0100
                Re: Set the result of void function "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-09-28 14:20 -0400
                Re: Set the result of void function Ian Collins <ian-news@hotmail.com> - 2017-09-29 07:52 +1300
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-28 11:59 -0700
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-28 18:50 +0100
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 19:47 +0100
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 21:57 +0200
                Re: Set the result of void function "James R. Kuyper" <jameskuyper@verizon.net> - 2017-09-28 16:14 -0400
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-28 13:17 -0700
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 21:23 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 13:55 -0700
                Re: Set the result of void function Gareth Owen <gwowen@gmail.com> - 2017-09-29 19:50 +0100
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-28 13:57 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-28 23:18 +0200
                Re: Set the result of void function "James R. Kuyper" <jameskuyper@verizon.net> - 2017-09-28 17:38 -0400
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-28 15:54 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-29 08:59 +0200
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 14:43 -0700
                Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-29 10:43 +0200
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-29 07:43 -0700
                Re: Set the result of void function Gareth Owen <gwowen@gmail.com> - 2017-09-30 19:21 +0100
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-30 19:45 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 13:31 -0700
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-28 13:41 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 14:07 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-28 16:25 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 18:45 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-28 19:54 -0700
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-28 20:51 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-28 22:39 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-29 09:16 -0700
                Re: Set the result of void function gazelle@shell.xmission.com (Kenny McCormack) - 2017-09-29 16:17 +0000
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-29 11:05 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-29 11:23 -0700
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-29 12:15 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-29 16:04 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-29 16:44 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-30 10:04 -0700
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-30 10:33 -0700
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-29 11:26 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-29 16:03 -0700
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-29 09:44 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-29 11:15 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-29 11:35 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-29 16:11 -0700
                Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-29 16:14 -0700
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-30 08:55 -0700
                Re: Set the result of void function jameskuyper@verizon.net - 2017-09-29 11:36 -0700
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-29 12:05 +0100
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-29 12:17 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-29 09:15 -0700
                Re: Set the result of void function Ian Collins <ian-news@hotmail.com> - 2017-09-29 09:42 +1300
                Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-28 21:55 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 14:12 -0700
                Re: Set the result of void function "James R. Kuyper" <jameskuyper@verizon.net> - 2017-09-28 17:22 -0400
                Re: Set the result of void function Gareth Owen <gwowen@gmail.com> - 2017-09-29 19:50 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 09:00 -0700
                Re: Set the result of void function supercat@casperkitty.com - 2017-09-28 09:35 -0700
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-28 10:57 -0700
                Re: Set the result of void function Thiago Adams <thiago.adams@gmail.com> - 2017-09-25 10:35 -0700
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-25 06:57 -0700
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-25 16:32 +0100
                Re: Set the result of void function Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-09-25 08:43 -0700
                Re: Set the result of void function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-09-25 22:12 +0100
                Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-25 09:03 -0700
                Re: Set the result of void function Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-09-25 14:17 +0000
          Re: Set the result of void function "James R. Kuyper" <jameskuyper@verizon.net> - 2017-09-20 11:32 -0400
        Re: Set the result of void function fir <profesor.fir@gmail.com> - 2017-09-20 01:50 -0700
          Re: Set the result of void function David Kleinecke <dkleinecke@gmail.com> - 2017-09-20 15:56 -0700
  Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-19 23:01 +0100
    Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-20 15:40 +0200
      Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-20 08:50 -0700
        Re: Set the result of void function David Brown <david.brown@hesbynett.no> - 2017-09-20 22:52 +0200
          Re: Set the result of void function supercat@casperkitty.com - 2017-09-20 15:04 -0700
    Re: Set the result of void function supercat@casperkitty.com - 2017-09-20 07:39 -0700
  Re: Set the result of void function jameskuyper@verizon.net - 2017-09-19 15:18 -0700
    Re: Set the result of void function bartc <bc@freeuk.com> - 2017-09-20 01:21 +0100
      Re: Set the result of void function jameskuyper@verizon.net - 2017-09-19 19:40 -0700
  Re: Set the result of void function rockbrentwood@gmail.com - 2017-09-19 16:36 -0700
    Re: Set the result of void function James Kuyper <jameskuyper@verizon.net> - 2017-09-19 22:13 -0400
    Re: Set the result of void function gazelle@shell.xmission.com (Kenny McCormack) - 2017-09-22 01:48 +0000
  Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-19 19:36 -0700
  Re: Set the result of void function mark.bluemel@gmail.com - 2017-09-20 01:00 -0700
    Re: Set the result of void function fir <profesor.fir@gmail.com> - 2017-09-20 02:01 -0700
  Re: Set the result of void function Keith Thompson <kst-u@mib.org> - 2017-09-20 08:36 -0700
  Re: Set the result of void function "James R. Kuyper" <jameskuyper@verizon.net> - 2017-09-20 11:36 -0400
  Re: Set the result of void function John Bode <jfbode1029@gmail.com> - 2017-09-20 15:30 -0700

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