[boost] Re: [addressof] patch for Borland

From: David Abrahams (dave_at_[hidden])
Date: 2005-03-14 17:25:09

"Eric Niebler" <eric_at_[hidden]> writes:

> 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.
> <<<

You might see if static_cast works there.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com