Re: Is C++11 to be default for GCC 4.9?

Re: Is C++11 to be default for GCC 4.9?

[pinskia]

> On Jan 24, 2014, at 1:26 AM, Marc Glisse <marc.glisse@inria.fr> wrote:
> 
> Wrong list, please send any follow-ups to gcc-help@gcc.gnu.org only.
> 
>> On Fri, 24 Jan 2014, Lars Hagström wrote:
>> 
>> I'm wondering whether GCC 4.9 will switch to -std=gnu++11 as default?
> 
> No. This is asked regularly, google should find the answer easily.

Considering GCC has not switched to c99 by default what makes someone think GCC should switch to c++11 by default?

-- Andrew

> 
>> I got an error that implies that "auto" is not usable, which would
>> mean that C++11 is not enabled, but I also got a warning that implied
>> that gnu++11 is "enabled by default".
>> 
>>> error: ‘xdir’ does not name a type
>> 
>>> warning: non-static data member initializers only available with -std=c++11 or -std=gnu++11 [enabled by default]
>> 
>> Or does the "enabled by default" bit mean something other than I think it means?
> 
> It is the warning that is enabled by default (in other messages you would see [-Wunused] or [-Wformat] etc to tell you which option controls this warning).
> 
> -- 
> Marc Glisse

Re: Is C++11 to be default for GCC 4.9?

[Lars Hagström]

Thanks for the quick answer, and sorry for posting to the wrong list.

In my defense I did google quite a lot and found some people thinking
that GCC might switch, and some that it might not.

And mainly I was just hopeful, since I was hoping that the ABI
compatibility issues with boost in linux package repositories would
resolve itself within a few years...

One reference from the Debian mailing lists:
https://lists.debian.org/debian-devel/2013/08/msg00117.html

Anyway, thanks again. And now I'll have to go and reconsider my
alternatives of if I can get to use C++11...

/Lars

On Fri, Jan 24, 2014 at 10:36 AM,  <pinskia@gmail.com> wrote:
>
>
>> On Jan 24, 2014, at 1:26 AM, Marc Glisse <marc.glisse@inria.fr> wrote:
>>
>> Wrong list, please send any follow-ups to gcc-help@gcc.gnu.org only.
>>
>>> On Fri, 24 Jan 2014, Lars Hagström wrote:
>>>
>>> I'm wondering whether GCC 4.9 will switch to -std=gnu++11 as default?
>>
>> No. This is asked regularly, google should find the answer easily.
>
> Considering GCC has not switched to c99 by default what makes someone think GCC should switch to c++11 by default?
>
> -- Andrew
>
>>
>>> I got an error that implies that "auto" is not usable, which would
>>> mean that C++11 is not enabled, but I also got a warning that implied
>>> that gnu++11 is "enabled by default".
>>>
>>>> error: ‘xdir’ does not name a type
>>>
>>>> warning: non-static data member initializers only available with -std=c++11 or -std=gnu++11 [enabled by default]
>>>
>>> Or does the "enabled by default" bit mean something other than I think it means?
>>
>> It is the warning that is enabled by default (in other messages you would see [-Wunused] or [-Wformat] etc to tell you which option controls this warning).
>>
>> --
>> Marc Glisse

Re: Is C++11 to be default for GCC 4.9?

[Jonathan Wakely]

On 24 January 2014 09:36,  <pinskia@gmail.com> wrote:
> Considering GCC has not switched to c99 by default what makes someone think GCC should switch to c++11 by default?

A switch might be appropriate at some point in the future. C++11 has
been better received by the C++ community than C99 was by the C
community.  From the people I talk to it seems that users who are
still using C++03 are doing so because they have to stick with an
older compiler. If they have a newer compiler available then a
significant proportion are using C++11.

That might be partly because Microsoft's compiler defaults to C++11
(whereas it doesn't even support C99!)

Re: Is C++11 to be default for GCC 4.9?

[Richard Sandiford]

Marc Glisse <marc.glisse@inria.fr> writes:
>> I got an error that implies that "auto" is not usable, which would
>> mean that C++11 is not enabled, but I also got a warning that implied
>> that gnu++11 is "enabled by default".
>>
>>> error: ‘xdir’ does not name a type
>>
>>> warning: non-static data member initializers only available with
>>> -std=c++11 or -std=gnu++11 [enabled by default]
>>
>> Or does the "enabled by default" bit mean something other than I think
>> it means?
>
> It is the warning that is enabled by default (in other messages you would 
> see [-Wunused] or [-Wformat] etc to tell you which option controls this 
> warning).

I can definitely sympathise with reading the message the other way though.
If that's the only output you see, the natural assumption is that the
"enabled by default" applies to the thing just before it.

Any objections to changing it to "this warning is enabled by default"
or "warning enabled by default"?  Or is that too verbose?

Thanks,
Richard

Re: Is C++11 to be default for GCC 4.9?

[Jonathan Wakely]

On 26 January 2014 16:17, Richard Sandiford wrote:
> I can definitely sympathise with reading the message the other way though.
> If that's the only output you see, the natural assumption is that the
> "enabled by default" applies to the thing just before it.
>
> Any objections to changing it to "this warning is enabled by default"
> or "warning enabled by default"?  Or is that too verbose?

The former seems far too verbose to me, I could live with the latter
(even though it's only a few characters shorter!)

Re: Is C++11 to be default for GCC 4.9?

[Florian Weimer]

On 01/26/2014 05:17 PM, Richard Sandiford wrote:
> Marc Glisse <marc.glisse@inria.fr> writes:
>>> I got an error that implies that "auto" is not usable, which would
>>> mean that C++11 is not enabled, but I also got a warning that implied
>>> that gnu++11 is "enabled by default".
>>>
>>>> error: ‘xdir’ does not name a type
>>>
>>>> warning: non-static data member initializers only available with
>>>> -std=c++11 or -std=gnu++11 [enabled by default]
>>>
>>> Or does the "enabled by default" bit mean something other than I think
>>> it means?
>>
>> It is the warning that is enabled by default (in other messages you would
>> see [-Wunused] or [-Wformat] etc to tell you which option controls this
>> warning).
>
> I can definitely sympathise with reading the message the other way though.
> If that's the only output you see, the natural assumption is that the
> "enabled by default" applies to the thing just before it.
>
> Any objections to changing it to "this warning is enabled by default"
> or "warning enabled by default"?  Or is that too verbose?

We should show the flag that enables the warning, so that users can use 
the -Wno- variant to disable it if they want.  Or does "enabled by 
default" mean that no such -Wno- flag exists?

-- 
Florian Weimer / Red Hat Product Security Team

Re: Is C++11 to be default for GCC 4.9?

[Marc Glisse]

On Mon, 27 Jan 2014, Florian Weimer wrote:

> On 01/26/2014 05:17 PM, Richard Sandiford wrote:
>> Any objections to changing it to "this warning is enabled by default"
>> or "warning enabled by default"?  Or is that too verbose?

The second one looks fine to me, need to find a real reviewer now ;-)

> We should show the flag that enables the warning, so that users can use the 
> -Wno- variant to disable it if they want.  Or does "enabled by default" mean 
> that no such -Wno- flag exists?

Exactly. -std=c++11 is the right way to make this warning quiet.

-- 
Marc Glisse