Re: Learning C as an existing programmer

From	Malcolm McLean <malcolm.mclean5@btinternet.com>
Newsgroups	comp.lang.c
Subject	Re: Learning C as an existing programmer
Date	2012-06-28 04:28 -0700
Organization	http://groups.google.com
Message-ID	<8a24da01-8012-41e3-92a9-ef81237ffd29@googlegroups.com> (permalink)
References	(4 earlier) <kfn395j6q1l.fsf@x-alumni2.alumni.caltech.edu> <bda5d3c6-fcef-4a3a-8cc3-d9f4186fee97@googlegroups.com> <kfntxxy5j40.fsf@x-alumni2.alumni.caltech.edu> <malloc-20120626152807@ram.dialup.fu-berlin.de> <kfnd34m5f10.fsf@x-alumni2.alumni.caltech.edu>

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בתאריך יום שלישי, 26 ביוני 2012 15:22:35 UTC+1, מאת Tim Rentsch:
> ram@zedat.fu-berlin.de (Stefan Ram) writes:
> 
> You snipped too much context.  If a piece of code isn't
> able to deal with an allocation failure, it doesn't matter
> where the allocation falure came from.  If a piece of
> code is able to deal with allocation failure in some way,
> that applies equally to allocation failures for malloc()
> and VLAs, assuming of course that VLA allocation failure
> can be detected, which I pointed out upthread that it
> can in a conforming implementation, if the implementation
> so desires.  The ability or non-ability of some piece of
> code to respond sensibly to allocation failure has no
> bearing on the point I was making.
>
We're talking about libraries.

I want to find the convex hull of a set of points. The algorithm I'm using needs a temporary buffer.

With malloc() we write

int convexhull(double *x, double *y, int N, double *xout, double *yout)
{
  void *ptr;
  int Nhullpoints;

  ptr = malloc(sizeof(double) * 2 * N);
  if(!ptr)
    return -1;
  Nhullpoints = dothegubbins(x, y, N, xout, yout, ptr); 
  return Nhullpoints;
}

with a vla it's a bit more difficult to provide a corresponding solution.

Thread

Learning C as an existing programmer rammy <nospam@nospam.com> - 2012-06-24 21:52 +0000
  Re: Learning C as an existing programmer Ian Collins <ian-news@hotmail.com> - 2012-06-25 10:26 +1200
    Re: Learning C as an existing programmer "Charles Richmond" <numerist@aquaporin4.com> - 2012-06-24 18:28 -0500
      Re: Learning C as an existing programmer "Joe." <antelope3@news.net> - 2012-06-25 01:05 -0600
      Re: Learning C as an existing programmer "Joe." <antelope3@news.net> - 2012-06-25 01:10 -0600
        Re: Learning C as an existing programmer Weland <weland@faeroes.freeshell.org> - 2012-06-25 08:20 +0000
          Re: Learning C as an existing programmer "Joe." <antelope3@news.net> - 2012-07-02 01:46 -0600
      Re: Learning C as an existing programmer Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> - 2012-06-25 20:37 +0000
        Re: Learning C as an existing programmer James Kuyper <jameskuyper@verizon.net> - 2012-06-25 16:51 -0400
        Re: Learning C as an existing programmer Keith Thompson <kst-u@mib.org> - 2012-06-25 14:25 -0700
          Re: Learning C as an existing programmer Les Cargill <lcargill99@comcast.com> - 2012-06-25 17:50 -0500
          Re: Learning C as an existing programmer William Ahern <william@wilbur.25thandClement.com> - 2012-06-25 16:52 -0700
        Re: Learning C as an existing programmer Les Cargill <lcargill99@comcast.com> - 2012-06-25 17:49 -0500
        Re: Learning C as an existing programmer nick_keighley_nospam@hotmail.com - 2012-06-26 00:09 -0700
    Re: Learning C as an existing programmer "Joe." <antelope3@news.net> - 2012-06-25 00:55 -0600
    Re: Learning C as an existing programmer Nachy <mazwolfe@gmail.com> - 2012-06-25 13:26 -0700
      Re: Learning C as an existing programmer James Kuyper <jameskuyper@verizon.net> - 2012-06-25 17:07 -0400
      Re: Learning C as an existing programmer Nachy <mazwolfe@gmail.com> - 2012-06-25 14:56 -0700
        Re: Learning C as an existing programmer James Kuyper <jameskuyper@verizon.net> - 2012-06-25 18:29 -0400
        Re: Learning C as an existing programmer pete <pfiland@mindspring.com> - 2012-06-25 18:56 -0400
          Re: Learning C as an existing programmer nick_keighley_nospam@hotmail.com - 2012-06-26 00:21 -0700
            Re: Learning C as an existing programmer Robert Wessel <robertwessel2@yahoo.com> - 2012-06-26 02:56 -0500
            Re: Learning C as an existing programmer Ike Naar <ike@sverige.freeshell.org> - 2012-06-26 08:10 +0000
        Re: Learning C as an existing programmer "J. J. Farrell" <jjf@bcs.org.uk> - 2012-06-26 07:06 +0100
      Re: Learning C as an existing programmer nick_keighley_nospam@hotmail.com - 2012-06-26 00:18 -0700
        Re: Learning C as an existing programmer Keith Thompson <kst-u@mib.org> - 2012-06-26 00:23 -0700
        Re: Learning C as an existing programmer James Kuyper <jameskuyper@verizon.net> - 2012-06-26 06:47 -0400
  Re: Learning C as an existing programmer Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-25 01:21 +0100
  Re: Learning C as an existing programmer "Joe." <antelope3@news.net> - 2012-06-25 00:54 -0600
  Re: Learning C as an existing programmer David Brown <david@westcontrol.removethisbit.com> - 2012-06-25 09:19 +0200
    Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-06-25 11:15 +0100
      Re: Learning C as an existing programmer "Ronald Benedik" <Aon.912717285@aon.at> - 2012-06-25 12:30 +0200
        Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-06-25 11:43 +0100
          Re: Learning C as an existing programmer "Ronald Benedik" <Aon.912717285@aon.at> - 2012-06-25 12:55 +0200
      Re: Learning C as an existing programmer Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-06-25 10:38 +0000
        Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-06-25 13:05 +0100
      Re: Learning C as an existing programmer Heikki Kallasjoki <fis+usenet@zem.fi> - 2012-06-25 10:56 +0000
      Re: Learning C as an existing programmer David Brown <david@westcontrol.removethisbit.com> - 2012-06-25 13:34 +0200
        Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-06-25 12:43 +0100
          Re: Learning C as an existing programmer David Brown <david@westcontrol.removethisbit.com> - 2012-06-25 15:16 +0200
            Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-06-25 14:39 +0100
              Re: Learning C as an existing programmer David Brown <david@westcontrol.removethisbit.com> - 2012-06-26 11:07 +0200
                Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-06-26 12:05 +0100
                Re: Learning C as an existing programmer David Brown <david@westcontrol.removethisbit.com> - 2012-06-26 14:28 +0200
            Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-06-25 14:39 +0100
    Re: Learning C as an existing programmer 88888 Dihedral <dihedral88888@googlemail.com> - 2012-06-25 18:21 -0700
      Re: Learning C as an existing programmer David Brown <david@westcontrol.removethisbit.com> - 2012-06-26 11:03 +0200
  Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-25 00:50 -0700
    Re: Learning C as an existing programmer Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-25 11:50 +0100
      Re: Learning C as an existing programmer gwowen <gwowen@gmail.com> - 2012-06-25 04:32 -0700
        Re: Learning C as an existing programmer Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-25 14:25 +0100
          Re: Learning C as an existing programmer gwowen <gwowen@gmail.com> - 2012-06-26 02:38 -0700
            Re: Learning C as an existing programmer jacob navia <jacob@spamsink.net> - 2012-06-26 12:13 +0200
              Re: Learning C as an existing programmer jacob navia <jacob@spamsink.net> - 2012-06-26 12:15 +0200
              Re: Learning C as an existing programmer Ian Collins <ian-news@hotmail.com> - 2012-06-26 23:08 +1200
            Re: Learning C as an existing programmer Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-27 01:55 +0100
              Re: Learning C as an existing programmer 88888 Dihedral <dihedral88888@googlemail.com> - 2012-06-26 18:43 -0700
        Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-25 14:27 -0700
          Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-26 00:18 -0700
            Re: Learning C as an existing programmer nick_keighley_nospam@hotmail.com - 2012-06-26 04:02 -0700
            Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-26 05:54 -0700
              Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-26 07:22 -0700
                Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-28 04:28 -0700
                Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-29 10:07 -0700
                Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-07-02 08:57 -0700
                Re: Learning C as an existing programmer gwowen <gwowen@gmail.com> - 2012-07-03 03:26 -0700
                Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-06 16:28 -0700
                Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-06 18:16 -0700
                Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-07-07 04:51 -0700
                Re: Learning C as an existing programmer Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-07 16:48 +0100
                Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-07-07 09:07 -0700
                Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-07 12:27 -0700
              Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-07-03 15:01 +0100
                Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-06 16:13 -0700
                Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-07-07 19:35 +0100
                Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-07-07 11:52 -0700
                Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-07 19:40 -0700
          Re: Learning C as an existing programmer gwowen <gwowen@gmail.com> - 2012-06-26 03:03 -0700
            Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-26 06:34 -0700
            Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-26 06:40 -0700
            Re: Learning C as an existing programmer Gareth Owen <gwowen@gmail.com> - 2012-06-27 07:16 +0100
              Re: Learning C as an existing programmer James Kuyper <jameskuyper@verizon.net> - 2012-06-27 06:48 -0400
            Re: Learning C as an existing programmer "io_x" <a@b.c.invalid> - 2012-06-28 09:18 +0200
              Re: Learning C as an existing programmer nick_keighley_nospam@hotmail.com - 2012-06-28 02:02 -0700
                Re: Learning C as an existing programmer "io_x" <a@b.c.invalid> - 2012-06-28 12:19 +0200
          Re: Learning C as an existing programmer Rui Maciel <rui.maciel@gmail.com> - 2012-07-03 15:00 +0100
            Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-06 15:56 -0700
              Re: Learning C as an existing programmer Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-07-07 09:18 -0700
                Re: Learning C as an existing programmer Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-07 11:56 -0700

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