Boost C++ Libraries: Ticket #4637: An extra scoped_array(n) constructor, please!

attachment set

niels_dekker — Wed, 08 Sep 2010 09:37:58 GMT

attachment → extra_scoped_array_constructor.patch

olafvdspek@… — Thu, 03 Nov 2011 12:19:58 GMT

Hoi Niels,

You used "new T[]()" instead of "new T[]". Do you require the former or would the latter be fine for you? Not everyone needs the elements to be initialized. Initializing them after construction is possible, uninitializing them isn't.

niels_dekker — Thu, 03 Nov 2011 14:22:01 GMT

Hoi Olaf,

Thanks for your feedback. I prefer to have the elements value-initialized by such a scoped_array(n) constructor. That's also consistent with the interface of std::vector:

   // All 'n' elements value-initialized:
   boost::scoped_array<my_type> a(n);
   std::vector<my_type> v(n);

People who really need to have uninitialized elements can still use the old (verbose) syntax, of course...

Thu, 03 Nov 2011 15:06:36 GMT

Replying to niels_dekker:

Hoi Olaf,

Thanks for your feedback. I prefer to have the elements value-initialized by such a scoped_array(n) constructor.

The difference only applies to types without constructors (AFAIK).

That's also consistent with the interface of std::vector:
   // All 'n' elements value-initialized:
   boost::scoped_array<my_type> a(n);
   std::vector<my_type> v(n);
People who really need to have uninitialized elements can still use the old (verbose) syntax, of course...

That argument applies to not initializing as well. I can't remember ever using new T[]() actually. What use cases do you have for it?

niels_dekker — Sat, 05 Nov 2011 13:12:29 GMT

For the record, this subject is being discussed at [boost] [smart_ptr] scoped_array / shared_array (size_t) constructor, starting at http://lists.boost.org/Archives/boost/2011/10/187198.php