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Re: Add c++11 to USE_LANGUAGES

On 14 April 2017 at 15:25, Greg Troxel <> wrote:
> This is clearly not hard to implement.  The only real question is how
> much it hurts, in which ways on which platforms, and what the default
> should be.
> I am offering the following to be constructive on the path to
> improvement, since we need to get concrete, but I do not hold any of
> these positions strongly:
>   - Add c++11 and c++14 to USE_LANGUAGES.  Have it add GCC_REQD of 48
>     and 49.  Be ok with ++14 choosing 5 or 6 in not too long if we
>     figure out that 4.9's C++14 support isn't good enough for most.
>   - Figure out what to do about --std and be consistent.
>   - For packages declaring c++11/c++14, remove GCC_REQD if it follows
>     the standard rules.


>   - On platforms with < 4.8 native, choose 6 as default.  (Once you have
>     to build, might as well be modern.)

Based on a commit message, this may not be feasible for illumos (there
is no support for 6 yet).

>   - On platforms with 4.8 native, choose 4.8.   Accept some issues with
>     c++14, at least for now.
>   - On platforms with > 4.8 native, choose the native version.
>   - In all cases, let the user override the choice of default.

I've not looked into the implementation details but that seems reasonable.

>   - Add logic to fail if GCC_REQD is > than the chosen version, at least
>     if some c++ flavor is in USE_LANGUAGES.

To thwart USE_LANGUAGES=c++11 & GCC_REQD=5.3 being set?

>   - Perhaps allow different compilers for plain C, perhaps not.

This would only become effective upon building something which sets
one of those two language settings or are you thinking anything which
requires c++?


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