[boost] Re: [addressof] patch for Borland

From: Eric Niebler (eric_at_[hidden])
Date: 2005-03-14 15:06:50

Eric Niebler wrote:
> Peter Dimov wrote:
> 
>> Eric Niebler wrote:
>>
>>>> +// Borland doesn't like casting an array reference to a char
>>>> reference +// but thes overloads work around the problem.
>>>> +# if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
>>>> +template<typename T,std::size_t N>
>>>> +T (*addressof(T (&t)[N]))[N]
>>>> +{
>>>> +   return reinterpret_cast<T(*)[N]>(&t);
>>>> +}
>>
>>
>>
>> Why are you reinterpret_casting &t to itself? Is this a Borland 
>> problem as well?
> 
> 
> 
> Russell added the reinterpret_casts to my patch. Russell, can you comment?
> 

And here is Russell's reply. Looks like it's necessary.

 >>>
Truth is, I'm not sure why I reinterpret_cast t to its own type, but 
without it (i.e just return &t as Eric's original solution), FOREACH 
still gives these errors

[C++] main.cpp(1):
[C++ Error] addressof.hpp(42): E2034 Cannot convert 'int *' to 'int ( *)[5]'
[C++ Error] addressof.hpp(49): E2034 Cannot convert 'const int *' to 
'int ( *) const[5]'

As far as I can tell, the reinterpret_cast I've added isn't casting t to 
itself, as t is a T(&)[N], I'm reinterpret_casting it to the function 
return type, T(*)[N].

If this is incorrect, I can try other solutions if anyone has any 
suggestions, but just return &t doesn't work with bcc32-5.6.4.
<<<

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com