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Re: Length of C++ arrays allocated by operator new[]

From yatremblay@bel1lin202.(none) (Yannick Tremblay)
Newsgroups comp.lang.c++
Subject Re: Length of C++ arrays allocated by operator new[]
Date 2011-08-22 11:26 +0000
Organization A noiseless patient Spider
Message-ID <j2teco$l6f$1@dont-email.me> (permalink)
References <4e4fb013$0$6568$9b4e6d93@newsspool3.arcor-online.net> <j2on8h$h4u$1@gregory.bnet.hr> <0YKdndDjrZg9f9LTnZ2dnUVZ8jSdnZ2d@giganews.com> <4e516d11$0$7610$9b4e6d93@newsspool1.arcor-online.net>

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In article <4e516d11$0$7610$9b4e6d93@newsspool1.arcor-online.net>,
Marcel Müller  <news.5.maazl@spamgourmet.org> wrote:
>On 20.08.11 18.36, Leigh Johnston wrote:
>> On 20/08/2011 17:26, A wrote:
>>>> SomeClass* array = new SomeClass[10];
>>>>
>>>> size_t length = get_length_of_array(array); // Impossible
>>>
>>> any particular reason you don't want to use vector instead and then use
>>> vect::size ?
>
>- The old platform does not support STL well.

Really?  What's that old platform?  I was using the STL in
old compilers in the last century simply by adding STLPort to the
project. 

>- STL causes the executable size to explode. One disadvantage of 
>template meta programming over generics. (Of course, there are many 
>advantages on the other side.)

"Explode" is a bit strong.  But yes, it will increase a bit but you
seem to totally ignore the "Of course, there are many advantages on
the other side."   Don't just say it.  Seriously consider it.

>> Yes, well said. std::vector should be preferred over dynamic arrays for
>> most cases;
>
>std::vector has the major disadvantage that any piece of code that has 
>write access to its elements can also change its size and, more 
>importantly, cause reallocations. That's sometimes not wanted and could 
>cause hard to find bugs with UB, especially if the array is shared 
>between threads.

Euh, how is it different from raw dynamic arrays?  They have been
source of hard to find bugs for as long as programming has existed.
Bad programming is bad programming.  At least std::vector gives you
the tools to encourage or event enforce better programming.

The problems you list above can be handled simply be controlling
access (using const by default unless write access is needed) or as
proposed elsewhere by offering a more constrained interface via
composition.

If you really share raw arrays between threads directly, I suggest that
you have a much more fundamental problem to address that the possible
reallocation that a std::vector may do.  

Yan

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Length of C++ arrays allocated by operator new[] Marcel Müller <news.5.maazl@spamgourmet.org> - 2011-08-20 15:01 +0200
  Re: Length of C++ arrays allocated by operator new[] Richard Damon <richard@damon-family.org> - 2011-08-20 11:39 -0400
    Re: Length of C++ arrays allocated by operator new[] Marcel Müller <news.5.maazl@spamgourmet.org> - 2011-08-21 22:15 +0200
      Re: Length of C++ arrays allocated by operator new[] Richard Damon <richard@damon-family.org> - 2011-08-22 12:56 -0400
        Re: Length of C++ arrays allocated by operator new[] Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-22 22:41 +0200
  Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-20 09:20 -0700
    Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-20 10:38 -0700
      Re: Length of C++ arrays allocated by operator new[] ruben safir <ruben@mrbrklyn.com> - 2011-08-21 22:33 -0400
        Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-22 03:05 -0700
          Re: Length of C++ arrays allocated by operator new[] ruben safir <ruben@mrbrklyn.com> - 2011-08-22 20:05 -0400
            Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-22 17:20 -0700
            Re: Length of C++ arrays allocated by operator new[] Paul Brettschneider <paul.brettschneider@yahoo.fr> - 2011-08-23 08:18 +0200
            Re: Length of C++ arrays allocated by operator new[] James Kanze <james.kanze@gmail.com> - 2011-08-26 08:29 -0700
              Re: Length of C++ arrays allocated by operator new[] Noah Roberts <roberts.noah@gmail.com> - 2011-08-26 09:06 -0700
    Re: Length of C++ arrays allocated by operator new[] Juha Nieminen <nospam@thanks.invalid> - 2011-08-20 17:55 +0000
      Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-20 10:59 -0700
      Re: Length of C++ arrays allocated by operator new[] legalize+jeeves@mail.xmission.com (Richard) - 2011-08-21 03:07 +0000
  Re: Length of C++ arrays allocated by operator new[] "A" <a@a.a> - 2011-08-20 18:26 +0200
    Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-20 17:36 +0100
      Re: Length of C++ arrays allocated by operator new[] Marcel Müller <news.5.maazl@spamgourmet.org> - 2011-08-21 22:39 +0200
        Re: Length of C++ arrays allocated by operator new[] Ian Collins <ian-news@hotmail.com> - 2011-08-22 09:08 +1200
        Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-21 22:32 +0100
          Re: Length of C++ arrays allocated by operator new[] Marcel Müller <news.5.maazl@spamgourmet.org> - 2011-08-22 00:01 +0200
            Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-22 00:04 +0100
              Re: Length of C++ arrays allocated by operator new[] Ian Collins <ian-news@hotmail.com> - 2011-08-22 11:38 +1200
                Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-22 01:14 +0100
                Re: Length of C++ arrays allocated by operator new[] Ian Collins <ian-news@hotmail.com> - 2011-08-22 12:27 +1200
              Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-21 17:34 -0700
                Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-22 01:39 +0100
                Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-21 18:13 -0700
                Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-22 12:16 +0100
                Re: Length of C++ arrays allocated by operator new[] Paul <pchristor@yahoo.co.uk> - 2011-08-22 09:09 -0700
                Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-22 17:22 +0100
                Re: Length of C++ arrays allocated by operator new[] Oliver Jackson <chexmofo@hotmail.com> - 2011-08-22 22:50 -0700
              Re: Length of C++ arrays allocated by operator new[] Juha Nieminen <nospam@thanks.invalid> - 2011-08-22 06:10 +0000
                Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-22 12:20 +0100
                Re: Length of C++ arrays allocated by operator new[] Noah Roberts <roberts.noah@gmail.com> - 2011-08-26 09:03 -0700
                Re: Length of C++ arrays allocated by operator new[] Nobody <nobody@nowhere.com> - 2011-08-27 02:05 +0100
          Re: Length of C++ arrays allocated by operator new[] Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-08-22 02:06 -0700
        Re: Length of C++ arrays allocated by operator new[] Juha Nieminen <nospam@thanks.invalid> - 2011-08-22 06:06 +0000
          Re: Length of C++ arrays allocated by operator new[] Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-22 09:19 +0200
            Re: Length of C++ arrays allocated by operator new[] Goran <goran.pusic@gmail.com> - 2011-08-22 04:50 -0700
            Re: Length of C++ arrays allocated by operator new[] Juha Nieminen <nospam@thanks.invalid> - 2011-08-22 13:53 +0000
              Re: Length of C++ arrays allocated by operator new[] yatremblay@bel1lin202.(none) (Yannick Tremblay) - 2011-08-23 09:40 +0000
                Re: Length of C++ arrays allocated by operator new[] Juha Nieminen <nospam@thanks.invalid> - 2011-08-23 10:03 +0000
        Re: Length of C++ arrays allocated by operator new[] yatremblay@bel1lin202.(none) (Yannick Tremblay) - 2011-08-22 11:26 +0000
          Re: Length of C++ arrays allocated by operator new[] Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-22 22:32 +0200
      Re: Length of C++ arrays allocated by operator new[] Noah Roberts <roberts.noah@gmail.com> - 2011-08-27 13:30 -0700
        Re: Length of C++ arrays allocated by operator new[] Leigh Johnston <leigh@i42.co.uk> - 2011-08-27 22:23 +0100
  Re: Length of C++ arrays allocated by operator new[] Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-08-22 02:14 -0700
  Re: Length of C++ arrays allocated by operator new[] Gerald Breuer <Gerald.Breuer@Use-Author-Supplied-Address.invalid> - 2011-08-27 22:35 +0200
    Re: Length of C++ arrays allocated by operator new[] Noah Roberts <roberts.noah@gmail.com> - 2011-08-27 15:45 -0700
      Re: Length of C++ arrays allocated by operator new[] Paavo Helde <myfirstname@osa.pri.ee> - 2011-08-28 02:00 -0500
    Re: Length of C++ arrays allocated by operator new[] "Bo Persson" <bop@gmb.dk> - 2011-08-28 16:38 +0200
      Re: Length of C++ arrays allocated by operator new[] Gerald Breuer <Gerald.Breuer@Use-Author-Supplied-Address.invalid> - 2011-08-28 16:49 +0200
        Re: Length of C++ arrays allocated by operator new[] "Bo Persson" <bop@gmb.dk> - 2011-08-28 22:44 +0200
          Re: Length of C++ arrays allocated by operator new[] Gerald Breuer <Gerald.Breuer@Use-Author-Supplied-Address.invalid> - 2011-08-28 23:03 +0200
        Re: Length of C++ arrays allocated by operator new[] James Kanze <james.kanze@gmail.com> - 2011-08-29 04:05 -0700

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