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Re: Tree implementation, ideas for keyboard input method needed

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Bubba <nickname@banelli.biz.invalid> writes:
> 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? :)

Undefined behavior.

If you're *lucky*, you'll happen to collide with an
implementation-defined identifier and your code will fail to compile.

If you're *unlucky*, your program works as you intended it to work, or
it will fail in subtle ways that are difficult to find.

The compiler and/or standard runtime library can do anything they like
with identifiers that start with "__", and nearly anything they like
with identifiers that start with a single underscore.  If you define
such an identifier yourself, it may or may not conflict with a
system-defined identifier.

So don't do that.

[...]

>> 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?

A "double pointer" could be either a pointer to a pointer, or a pointer
to type "double".  It's better to refer to it as a pointer-to-pointer.

Why a pointer to a pointer?  Don't ask me, it's your code; you declared
it with a pointer-to-pointer yourself.  All I did was replace the
typedef (which hides the fact that the type is a pointer) with its full
definition.

But in general, if you want a function to modify something of type foo,
you need to pass it a foo*.  In this case, "foo" happens to be a pointer
type itself.

[...]

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
    Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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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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