[Development] RFC: handling of C++ feature test macros

Lars Knoll lars.knoll at qt.io
Wed Sep 18 08:26:23 CEST 2019


> On 18 Sep 2019, at 01:37, Thiago Macieira <thiago.macieira at intel.com> wrote:
> 
> On Tuesday, 17 September 2019 16:05:34 PDT Giuseppe D'Angelo via Development 
> wrote:
>> While I agree that at the moment it has virtually never happened, it
>> doesn't mean it couldn't happen in the future. Even today we have
>> compilers such as MSVC with "living on the edge" compile flags
>> (/c++latest). Our users can use those, and thus potentially trigger
>> codepaths that on their specific compiler version are implemented in a
>> pre-Standard way.
>> 
>> So, how academic (I think should I say paranoid...) do we want to be?
> 
> Marc's proposal is that we should accept that these things are rare and simply 
> correct when they do happen. Since our code is tested with the currently 
> latest versions of all compilers, we're fairly sure that any such macro works 
> with the compilers that currently support the feature.
> 
> When a new compiler comes out with the feature, we may get compilation errors. 
> Our users understand that we cannot test things that don't exist, so older 
> versions can fail to compile on new compilers (or produce a lot of warnings). 
> Issuing fixes is enough.

I agree. No point in doing lots of additional work preemptively. Let’s fix them when they occur.

Cheers,
Lars



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