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Re: Tree implementation, ideas for keyboard input method needed

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On 01/16/2012 05:36 PM, Bubba wrote:
> Keith Thompson's log on stardate 16 sij 2012
> 
> I hoped for something like this in the first place, so thank you in 
> advance!
> 
>> Identifiers starting with underscores are reserved to the
>> implementation in most contexts.  Identifiers starting with two
>> underscores are reserved in all contexts.  You should never define
>> such identifiers yourself (unless you're writing code for a C
>> compiler or library implementation).
> 
> What are the repercussions of choosing wrong number of underscores? :)

Theoretically: the behavior of your program is undefined. This means
that the C standard places no restrictions on the behavior of the
resulting program. That's a bad thing, if there's any particular
behavior you want your program to have, since it might not have that
behavior. It's an even worse thing if there are any things your program
could do that you don't want it to do (such as erasing all of your
files), because there's a chance that it might do one of those things.

Practically: identifiers are reserved to the implementation, so they can
by used by the implementation for it's own purpose, without worrying
about the possibility that user code might interfere. Consider what
could go wrong with your program if __celltype is defined by the
implementation, inside stdlib.h, for some purpose. The best possible
outcome is that the compiler will notice two different conflicting
definitions for __celltype, and complain. The worst possibility is that
__celltype is defined in some way that produces no warning messages when
you misuse it.

>> And in fact I'd declare this as:
>>     struct celltype *make_root(labeltype label, struct celltype **t);
> 
> Could you please clarify the need for double pointer?

Please don't refer to that as a "double pointer". It's a pointer to a
pointer. a "double pointer" could be interpreted as referring to a
"double*".

I'll let Keith answer the rest of your question in more detail, since
it's his suggestion.
-- 
James Kuyper

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Thread

Tree implementation, ideas for keyboard input method needed Bubba <nickname@banelli.biz.invalid> - 2012-01-16 22:01 +0000
  Re: Tree implementation, ideas for keyboard input method needed Keith Thompson <kst-u@mib.org> - 2012-01-16 14:27 -0800
    Re: Tree implementation, ideas for keyboard input method needed Bubba <nickname@banelli.biz.invalid> - 2012-01-16 22:36 +0000
      Re: Tree implementation, ideas for keyboard input method needed Kaz Kylheku <kaz@kylheku.com> - 2012-01-16 22:53 +0000
      Re: Tree implementation, ideas for keyboard input method needed James Kuyper <jameskuyper@verizon.net> - 2012-01-16 18:06 -0500
      Re: Tree implementation, ideas for keyboard input method needed Keith Thompson <kst-u@mib.org> - 2012-01-16 16:41 -0800
    Re: Tree implementation, ideas for keyboard input method needed Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-16 23:01 +0000
      Re: Tree implementation, ideas for keyboard input method needed Shao Miller <sha0.miller@gmail.com> - 2012-01-16 19:49 -0500
        Re: Tree implementation, ideas for keyboard input method needed Keith Thompson <kst-u@mib.org> - 2012-01-16 17:46 -0800
  Re: Tree implementation, ideas for keyboard input method needed Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-16 22:29 +0000
    Re: Tree implementation, ideas for keyboard input method needed Bubba <nickname@banelli.biz.invalid> - 2012-01-16 22:38 +0000
    Re: Tree implementation, ideas for keyboard input method needed William Ahern <william@wilbur.25thandClement.com> - 2012-01-16 15:30 -0800
      Re: Tree implementation, ideas for keyboard input method needed Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-17 00:03 +0000
      Re: Tree implementation, ideas for keyboard input method needed Keith Thompson <kst-u@mib.org> - 2012-01-16 16:35 -0800
        Re: Tree implementation, ideas for keyboard input method needed cri@tiac.net (Richard Harter) - 2012-01-17 02:00 +0000
          Re: Tree implementation, ideas for keyboard input method needed Keith Thompson <kst-u@mib.org> - 2012-01-16 19:16 -0800
            Re: Tree implementation, ideas for keyboard input method needed cri@tiac.net (Richard Harter) - 2012-01-17 05:15 +0000
              Re: Tree implementation, ideas for keyboard input method needed Keith Thompson <kst-u@mib.org> - 2012-01-17 00:00 -0800
          Re: Tree implementation, ideas for keyboard input method needed Kaz Kylheku <kaz@kylheku.com> - 2012-01-17 04:04 +0000
  Re: Tree implementation, ideas for keyboard input method needed Kaz Kylheku <kaz@kylheku.com> - 2012-01-16 22:44 +0000
  Re: Tree implementation, ideas for keyboard input method needed Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-16 17:58 -0500
  Re: Tree implementation, ideas for keyboard input method needed ImpalerCore <jadill33@gmail.com> - 2012-01-16 19:36 -0800
    Re: Tree implementation, ideas for keyboard input method needed Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-16 23:33 -0500
      Re: Tree implementation, ideas for keyboard input method needed ImpalerCore <jadill33@gmail.com> - 2012-01-17 07:18 -0800
    Re: Tree implementation, ideas for keyboard input method needed "BartC" <bc@freeuk.com> - 2012-01-17 13:54 +0000
      Re: Tree implementation, ideas for keyboard input method needed ImpalerCore <jadill33@gmail.com> - 2012-01-17 07:39 -0800
    Re: Tree implementation, ideas for keyboard input method needed Kaz Kylheku <kaz@kylheku.com> - 2012-01-17 19:01 +0000
  Re: Tree implementation, ideas for keyboard input method needed jgk@panix.com (Joe keane) - 2012-01-18 21:21 +0000

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