Re: C++11 flags for jhbuild

[Kjell Ahlstedt <kjell ahlstedt bredband net>]

On 2015-07-20 02:21, Ian Martin wrote:
> On 20/07/15 01:45, Murray Cumming wrote:
> > On Sun, 2015-07-19 at 15:44 +0200, Murray Cumming wrote:
> > > On Sun, 2015-07-19 at 23:09 +1200, Ian Martin wrote:
> > > > Hi,
> > > > I'm trying to build gtkmm with jhbuild.  glibmm fails with a number of
> > > > warnings and errors starting with
> > > > > warning: identifier 'decltype' is a keyword in C++11 [-Wc++0x-compat]
> > > > >
> > > > > /opt/gnome/include/sigc++-2.0/sigc++/functors/functor_trait.h:91:3:
> > > > > warning: identifier 'nullptr' is a keyword in C++11 [-Wc++0x-compat]
> > > > >
> > > > > /opt/gnome/include/sigc++-2.0/sigc++/functors/functor_trait.h:91:36:
> > > > > error: 'decltype' has not been declared
> > > > >
> > > > > /opt/gnome/include/sigc++-2.0/sigc++/functors/functor_trait.h:96:44:
> > > > > error: 'nullptr' was not declared in this scope
> > > > >       = sizeof(check(static_cast<T_functor*>(nullptr))) == 
> > > > > sizeof(int)
> > > > I'm guessing this means I need to enable C++11 within jhbuild.  Do 
> > > > I do
> > > > this in my .jhbuildrc or should this be a compiler flag added 
> > > > within the
> > > > glibmm configure.ac?
> > > This seems to be a -Wc++0x-compat warning. Do you have that in your
> > > jhbuild config file somehow?
> > Or maybe you just need to run autogen.sh again.
> Excluding comments, my .jhbuildrc contains the following:
> > modulesets_dir = '/usr/share/jhbuild/modulesets'
> > modules = [ 'gtkmm', 'cairomm' ]
> > checkoutroot = '/data/checkout/gnome-source/'
> > prefix = '/opt/gnome'
> and rerunning ./autogen.sh gives the same errors.
>
> I've tried adding
> autogenargs='-std=c++11'
> to jhbuildrc, but that blocked glib building with "unknown compiler 
> flag  -std=c++11 ".
>
> I'm running Debian testing, and use C++11 in other projects without 
> any problem, so I assume my build chain is set up OK.
> > This seems to be a -Wc++0x-compat warning. Do you have that in your
> > jhbuild config file somehow?
> The warnings confirm this: one is
> > /opt/gnome/include/sigc++-2.0/sigc++/signal.h:257:7: warning: 'auto' 
> > changes meaning in C++11; please remove it [-Wc++0x-compat]
> >        auto tmp_ = end();
> I haven't added it myself.
>
> Update: can build glibmm by adding
> MM_AX_CXX_COMPILE_STDCXX_11([noext],[mandatory])
> to configure.ac
When you said that you build gtkmm with jhbuild, the people that have 
replied to your first post probably assumed (like myself) that you have 
let jhbuild pull all relevant modules from the master branch in the git 
repository very recently. 
MM_AX_CXX_COMPILE_STDCXX_11([noext],[mandatory]) was added to several 
configure.ac files about a week ago.
> I'm no autotools genius, but it looks to me like sigc++ is now 
> dependent on c++11, which is going to create dependencies for all 
> downstream projects.  If I'm correct, do you want me to create the bug 
> report and patches?
I don't think it's necessary. If you just get the latest versions of 
gtkmm and all modules it depends on, it should work. One exception 
though: if you use --enable-warnings=fatal on gtkmm, it does not work 
right now because of very recent deprecations in gtk+. That will soon be 
fixed even without a bug report.
> Ian.
>
> Ian