Re: [boost] [function] Placement new warnings from gcc 6

Subject: Re: [boost] [function] Placement new warnings from gcc 6
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2016-04-05 00:18:23

On 2016-04-05 06:45, Gavin Lambert wrote:
> Mere moments ago, quoth I:
>> On 4/04/2016 19:52, Andrey Semashev wrote:
>>> On 2016-04-04 04:35, Gavin Lambert wrote:
>>>> Could you do this with an anonymous union?  eg:
>>>>
>>>> union function_buffer
>>>> {
>>>>     mutable union function_buffer_members
>>>>     {
>>>>         ...
>>>>     };
>>>>     mutable char data[sizeof(function_buffer_members)];
>>>> };
>>>>
>>>> Haven't tested this; not sure if it's legal to get the sizeof a subtype
>>>> nested in the same scope like this, but it at least seems plausible.
>>>
>>> That is a named union in your example. And if it's anonymous then you
>>> have no name to apply sizeof to.
>>
>> Type name != member name.  It is still an anonymous union.
>
> Although on further reflection, allowing a tag name on an anonymous
> union might be a Microsoft-specific extension (though GCC can enable
> support for it via command-line parameter).

Oh, if that's a non-standard extension then I'm not aware of it.

> It's probably something that *ought* to be in the standard, but that
> probably doesn't help you much at this time.

I'd say it *should not* be in the standard as it is very confusing.