Re: Warn about bitfields larger than union

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

Putting the OP back in the To field ...

On 31 October 2011 16:09, Jonathan Wakely wrote:
> On 31 October 2011 15:15, Kevin P. Fleming wrote:
>> On 10/30/2011 01:12 PM, Jon Grant wrote:
>>>
>>> Hello
>>>
>>> I've uploaded a simple C program which shows my query:
>>>
>>> http://pastebin.com/BQmG0m3g
>>>
>>> Is there a way for GCC to warn when union size is exceeded by a bit-field?
>>
>> The 'union size' is determined from the largest member of the union.
>
> Indeed, I don't see how the compiler could know that you didn't mean
> to make the union larger than the first member.
>
> If you want to put checks in for that, use a static assertions of some kind:
>
> char static_assert[(sizeof(REG0) == sizeof(REG0.reg8bit))-1];
>