Re: Help in Building octave on ubuntu 12.04

[Abhinav Tripathi]

On Wed, May 25, 2016 at 10:51 PM, Mike Miller <address@hidden> wrote:
>
> On Wed, May 25, 2016 at 10:12:47 -0700, Rik wrote:
> > Funnily enough, there was e-mail on this subject just within the last week
> > on the mailing list.  The development branch of Octave is now using C++11
> > features and requires a compiler that supports that.  We used to have a
> > check for that in configure.ac so you would be warned early about
> > problems.  That was backed out in March.

 I probably missed that mail. Will check.
Well, even if C++11 is required, gcc 4.6 supports some c++11 features and unique_ptr is definitely there.
I was concerned that octave is using a wrong flag.

> > changeset:   21481:eebbb80bf6d9
> > user:        Mike Miller <address@hidden>
> > date:        Fri Mar 18 11:03:58 2016 -0700
> > summary:     build: Use gnulib module std-gnu11 to enable C11 and C++11
> > features
> >
> > changeset:   21480:eec0b7933e6a
> > user:        Mike Miller <address@hidden>
> > date:        Fri Mar 18 11:01:02 2016 -0700
> > summary:     Backed out changeset 0cf6c08cb252 for enabling C11 and C++11
> > features
> >
> > Some sort of check should probably be re-established so you don't waste a
> > lot of compile cycles before reaching a file that has std::unique_ptr in it.
>
> The check is still there, it will print something like
>
>   checking for g++ option to enable C++11 features... unsupported

Yes I saw that printed. But actually it found an option and it was not the correct option. Gcc 4.6 requires c++0x (atleast for unique_ptr)  while the displayed option was something else (probably which supports even less c++11).

> if the check fails. But configure carries on, it is not treated as a
> required option yet. We can easily add that to require the compiler to
> support C++11 at configure time.
>
> GCC 4.6 supports the c++0x option instead, and supports *some* C++11
> features, including std::unique_ptr, but maybe not all of the features
> that we are now using.
>
> Configuring with the argument CXX="g++ -std=gnu++0x" would be a useful
> test to see if we can still work with 4.6.
>

Hmm. I was actually looking for this. I'll try it tomorrow and share the result.

Abhinav