RFC: JEP JDK-8208089: Implement C++14 Language Features

[Kim Barrett]

> On Mar 2, 2020, at 7:00 AM, Andrew Haley <aph at redhat.com> wrote:
> 
> On 11/19/18 8:39 PM, Kim Barrett wrote:
>> I don't see any benefit to making the first C++ code change that uses
>> a new feature also incorporate the needed build system changes.
>> Indeed, how does one develop that feature usage unless one has the
>> build system changes already in hand?
>> 
>> It seems to me that if the documentation says one can use some new
>> language feature but the build system hasn't been updated to actually
>> support doing so, then the documentation is wrong. And recall that
>> this JEP includes making some new features available immediately.
>> (That initial list might be modified as part of this JEP discussion.)
> 
> What is the status of this? I thought we'd decide, but I still see
> 
>   $1_CXXSTD_CXXFLAG="-std=gnu++98"
> 
> in flags-cflags.m4
> 
> I need std::make_unsigned in order to fix some undefined behaviour in
> HotSpot. I could implement it myself in share/metaprogramming but if
> we've agreed to allow C++14, can we please get it done now? Thx.

In light of JEP 362 "Deprecate the Solaris and SPARC Ports"
https://bugs.openjdk.java.net/browse/JDK-8231554
with the intended removal of Oracle Developer Studio (aka Solaris
Studio) as a supported compiler sometime soon, we don't want to spend
effort getting HotSpot to production quality on that platform with
C++11/14 features enabled and in use.