CXXSTD=c++11

[Bryan Drewery]

On 3/24/2016 3:54 PM, Dimitry Andric wrote:
> On 24 Mar 2016, at 23:51, Bryan Drewery <bdrewery at FreeBSD.org> wrote:
>>
>> On 3/24/2016 3:45 PM, Bryan Drewery wrote:
>>> On 3/24/2016 3:44 PM, Dimitry Andric wrote:
>>>> On 24 Mar 2016, at 23:36, Bryan Drewery <bdrewery at FreeBSD.org> wrote:
>>>>>
>>>>> Is there any problem with forcing -std=c++11 for all CXX/LIB_CXX builds
>>>>> now?  We do this when using an external GCC since it doesn't default to
>>>>> the c++11 standard quite yet.  As far as I understand, we require c++11
>>>>> to build clang/libc++.
>>>>
>>>> Yes, but it already passes -std=c++11 in the correct places, as far as I
>>>> know.  E.g. during the clang and libc++ builds.
>>>>
>>>>
>>>>> It seems to be the problem at
>>>>> https://lists.freebsd.org/pipermail/freebsd-toolchain/2015-October/001757.html
>>>>> which I've fixed in an upcoming commit to properly pass -std=c++11 to
>>>>> the lib32 build in CXXFLAGS.
>>>>
>>>> Hm, is this occuring during the build of libcxxrt, or of libc++?  If it
>>>> is the former, then it seems that the system headers don't properly
>>>> declare _Static_assert() in that case.  I have no clue as to why, though
>>>> maybe it's picking something up from gcc's famously "fixed" standard
>>>> headers?
>>>>
>>>
>>> libcxxrt.
>>>
>>> My fix also includes passing the proper -isystem =/usr/include/c++/v1 path.
>>>
>>> I'll try without the -std change.
>>>
>>>
>>
>> It fails without -std=c++11 (there's more discussion in that link and in
>> PR 205453).
> 
> Yeah, I also commented on PR 205453 in the past, but I still don't
> understand where the external gcc gets its _Static_assert macro from.
> Or whether it gets it at all.  Maybe we should place a hack for this in
> sys/cdefs.h?  We shouldn't litter contrib code with #ifdef GCC_VERSION
> blocks.
> 

Well _Static_assert is C++11 and static_assert is C11. These files are
being built by GCC as C++03, so neither is presumably available without
raising the standard.

Shouldn't this be using static_assert with a CXXFLAGS+=-std=c++11 or
CSTD=c11 ?


-- 
Regards,
Bryan Drewery

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