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

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On 08/22/11 08:39 AM, Marcel Müller 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.
> - STL causes the executable size to explode.

Only if you have a very poor linker.

> One disadvantage of
> template meta programming over generics. (Of course, there are many
> advantages on the other side.)

Who mentioned template meta-programming?

>> 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.

Then derived privately and only expose a subset of members.  Or simply 
write your own array class.  Either way, the "avoid naked arrays" rule 
of thumb is still valid.

>> about the only case where one still needs to use dynamic
>> arrays is if you want to allocate but not initialize a buffer.
>
> Why? vector will always initialize /less/ or same than operator new[].
> The allocation size of the vector may be larger than logical size,
> containing additional uninitialized storage. new[] in contrast always
> invokes the standard constructors (if any).

So does vector's sized constructor.

-- 
Ian Collins

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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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