Re: [PATCH 2/2] Add gdb::string_view

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2018-03-19 08:21, Pedro Alves wrote:
>> Hmm, when building with older g++ (such as the aarch64 builders on the 
>> buildbot,
>> which have g++ 4.8), it trips on:
>> 
>>   using __idt = std::common_type_t<_Tp>;
>> 
>> It looks like that release of g++ didn't have std::common_type_t.  I 
>> guess it
>> would be possible to avoid using it, and change these:
> 
> It has std::common_type though.  C++14 std::foo_t types are usually 
> just a
> helper/convenience alias template, like:
> 
>   /// Alias template for common_type
>   template<typename... _Tp>
>     using common_type_t = typename common_type<_Tp...>::type;
> 
> So it sounds like we can just use the C++11 / ::type form directly, or
> add gdb::common_type_t somewhere, like common/traits.h or to our
> copy of string_view.

Ok thanks I think I got it to work now.

> 
>> 
>>     operator==(basic_string_view<_CharT, _Traits> __x,
>>                __detail::__idt<basic_string_view<_CharT, _Traits>> 
>> __y) noexcept
>> 
>> for
>> 
>>     operator==(basic_string_view<_CharT, _Traits> __x,
>>                basic_string_view<_CharT, _Traits> __y) noexcept
>> 
>> but I am not aware of what consequences it would have.
> 
> Would it be possible to import some of the libstdc++'s relevant
> testscases into our unit tests framework, like was done for
> gdb::optional [1]?
> 
> [1] https://sourceware.org/ml/gdb-patches/2017-04/msg00239.html

Good idea, I did it and it caught a few important compilation issues!

I just need to clean up the patches and I'll send a v2.

Thanks,

Simon