Re: Help in Building octave on ubuntu 12.04

[Mike Miller]

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.
> 
> 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

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.

-- 
mike