RFC: Move to C++14

[Christopher James Halse Rogers]

On Wed, Feb 18, 2015 at 12:08 AM, Alan Griffiths 
<alan.griffiths at canonical.com> wrote:
> On 17/02/15 12:37, Alexandros Frantzis wrote:
>>  Let me know what you think.
> 
> There are probably four important constituencies that need to build 
> Mir
> and they may well be targeting different platforms.
> 
> 1. Mir developers - they are clearly targeting vivid
> 2. Client-side "toolkit" developers - these could be targeting the LTS
> (trusty) or the stable release (utopic) as well as vivid
> 3. Server-side "Shell" developers - the ones we are aware of are
> targeting vivid
> 4. Graphics "platform" developers - there are none, but they would
> likely target the LTS (trusty)
> 
> So, there are reasons to support development on trusty.
> 
> Having said that, as the OP mentions C++14 support is only one of the
> issues:
> 
> We've currently got an MP that reworks a test so that it builds with 
> the
> version of gmock available on trusty. If we assume that only /1/ above
> needs to build the tests then we wouldn't need that.
> 
> IIUC it is also possible to install g++-4.9 on the LTS

Correct - the gcc-4.9 builds in 
https://launchpad.net/~ubuntu-toolchain-r/+archive/ubuntu/test?field.series_filter=trusty

This PPA is maintained by the Ubuntu toolchain folks, and is entirely 
parallel-installable with the existing 14.04 buildchain.

As we have no requirement to stick the latest Mir code in the 14.04 
archive I think requiring a safe PPA is not too onerous.

> 
> So I don't see using C++14 disenfranchising anyone that doesn't 
> already
> have issues.

Given the easy availability of a C++14 compiler on 14.04, I'm very much 
in favour of enabling C++14 features.