[Boost-users] Re: [array] accessing the underlying C array of a boost::array

From: Joao Abecasis (jpabecasis_at_[hidden])
Date: 2005-02-02 11:48:06

Hi!

I'll take up on this one since I'm somewhat aware of the issues... I 
hope I'm not way off line. (If I am, please educate me! ;) )

Frank Hess wrote:
> Does anyone know what the preferred method of accessing the underlying C array 
> of a boost::array is?  In boost 1.32 there is a data() member which returns a 
> const pointer, and a c_array() member which returns a pointer.  Also, the 
> elems member itself is public.

I think the "preferred" method is to use the data() member function 
because that's what will be part of std::tr1::array, in the upcoming 
Technical Report that extends the C++ Standard.

As you pointed out, though, to access the non-const pointer there is 
only the c_array() member in the current version of boost.

> But at 
> http://www.josuttis.com/cppcode/array.html, the author states that data() can 
> be used for both const and non-const pointers, and indeed it is so in the 
> version he posts on his website 
> http://www.josuttis.com/cppcode/array.hpp.html (which doesn't provide the 
> c_array() member but overloads data() instead).

This is a known "limitation" with the current version. IIUC, the plan is 
to update boost::array to reflect the changes introduced with TR1 for 
the next release. The c_array() member will probably be deprecated then.

If you have that option, my personal suggestion is that you use the 
up-to-date version posted at the author's site while you wait for the 
boost release that'll set things right.

Best regards,

Joćo Abecasis