Re: C++11 (abridged version)

[Pedro Alves <palves@redhat.com>]

On 10/20/2016 08:09 PM, Pedro Alves wrote:
> On 10/20/2016 08:05 PM, Eli Zaretskii wrote:
>>> From: Pedro Alves <palves@redhat.com>
>>> Date: Thu, 20 Oct 2016 18:07:58 +0100
>>>
>>> On #4 (policy for newer standard versions), as I've been saying many
>>> times in the past week, I think that what matters is whether there's
>>> reasonably widespread compiler availability, meaning the latest stable
>>> releases of distributions include a compiler for the standard, or it's
>>> easy to get one by installing some optional package.  If reasonably
>>> available, then we should switch, and take advantage of the great work
>>> our compiler and standards friends have been doing.
>>
>> IMO, this is too vague for a policy.  I proposed a much more
>> quantitative criterion, one that doesn't run the risk of triggering
>> long disputes with no clear-cut ways of making a decision.  I'm okay
>> with other criteria, as long as they are clear, easily applied, and
>> don't require subjective interpretation.
> 
> Agreed.  That's why I concluded with:
> 
> ~~~~
> Going forward past C++11, since "reasonable availability" is not
> quantifiable, Eli suggested the policy of
> 
>   "(...) waiting until the oldest compiler which supports that newer
>   standard is at least 3 years old (like GCC 4.8.1 is today)."
> 
> And I agree with that.  (I'd prefix it with "at least".)
> ~~~~
> 
> I hope to have not misquoted you.  If I have, I apologize.

Here's a straw man proposal for the policy text:

When is GDB going to start requiring C++NN ?

Our general policy is to wait until the oldest compiler which
supports C++NN is at least 3 years old.

Rationale: We want to ensure reasonably widespread compiler availability,
to lower barrier of entry to GDB contributions, and to make it easy for users
to easily build new GDB on currently supported stable distributions themselves.
3 years should be sufficient for latest stable releases of distributions to
include a compiler for the standard, and/or for new compilers to appear as
easily installable optional packages.  Requiring everyone to build a compiler
first before building GDB, which would happen if we required a too-new compiler,
would cause too much inconvenience.

WDYT?

Thanks,
Pedro Alves