On Jan 24, 2017 8:00 PM, "Edward Diener" <eldiener@tropicsoft.com> wrote:
>
> On 1/24/2017 9:13 AM, Stefan Seefeld wrote:
>>
>> On 24.01.2017 03:30, John Maddock wrote:
>>>
>>>
>>>>> Yes I have, I brought it up, nothing happened. I stopped using
>>>>> check_target_builds.
>>>>>
>>>>    The problem is that check_target_builds tries to
>>>> guess which features are important, and does it
>>>> badly (via a hard-coded list).

[…]

>> It seems this issue arises because b2 allows multiple build variants to
>> be built at once, so (at least theoretically) each would need to run its
>> own set of config checks.
>
>
> You don't need multiple build variants to generate the problem. Just build with a toolset for a compiler(-version) with a subfeature that sets -std=c++03, and then subsequently build with a compiler(-version) with a subfeature that sets -std=c++11.

To me that's two build variants, at least conceptually. How else would you combine builds with two ABI-incompatible flags ?

   Stefan