Further thoughts about Option 2...

I suspect that once we make it technically possible to use C++11 features, they will eventually start to "creep" into new code even if we tell people not to use them. I don't think we could even put in any technical restrictions to force people not to use them, because that could potentially break header inclusions.

@suv - Do you know what the oldest version of OS X is that fully supports the C++11 standard?

AV

On 24 August 2015 at 14:36, Alex Valavanis <valavanisalex@...400...> wrote:

Hi All,

Time to revisit our old discussions about C++11 support (with some urgency). It seems that unstable versions of libsigc++ (as of version 2.4.1, I think) require the C++11 standard to be enabled by the compiler [1]. This is already causing build failures [2] so we need to act soon. Indeed, as suv points out in [2], many of the Gnome development libraries have switched over too.

As far as I recall, older versions of OS X do not have a compiler that supports C++11 fully, so we'd risk killing off support for these users if we enforce the C++11 standard in Inkscape.

Some options...

1. Add configuration tests to selectively enable C++11 only on systems

with the new libraries... this could be complicated to maintain, though

2. Enforce C++11 builds, but forbid developers from using new features

until they have been tested on a wide range of systems... I'm not sure how we'd enforce this once we've made it technically possible to build C++11 code

3. Enforce C++11 builds, and give developers "green light" to use new

features. This is likely to cause problems for users of old OSes!

Best wishes,

AV

[1] https://git.gnome.org/browse/libsigc++2/commit/?id=5a6b8f21f83dfe0f64770196e... [2] https://bugs.launchpad.net/inkscape/+bug/1488079

On 2015-08-24 16:04 (+0200), su_v wrote:

On 2015-08-24 15:48 (+0200), Alex Valavanis wrote:

...

@suv - Do you know what the oldest version of OS X is that fully supports the C++11 standard?

AFAIK it is feasible with OS X 10.8 Mountain Lion (if switching C++ runtime to libc++); full native support came with OS X 10.9 Mavericks (libc++ is default):

...

The default C++ runtime on OS X 10.9 and later is libc++ which supports C++11 but on OS X 10.8 and earlier the default C++ runtime is a version of libstdc++ based on GCC 4.2.1 which does not support C++11.

Just to add - that last quote is from here: https://trac.macports.org/wiki/LibcxxOnOlderSystems which details how C++11 support could be enabled on older systems - there's no guarantee though that it works (any package might fail to compile for various reasons - recent example is ncurses 6.0 which fails to build on Lion if MacPorts was configured to use 'libc++' as default C++ runtime). Overall, the effort seems rather huge ((temporary) disk space requirements for llvm+clang, build times for multiple llvm ports and frequent updates) and is likely to break apart easily - without having full upstream support in MacPorts. It is also unknown whether (self-contained and relocatable) application bundles based on such a custom tool chain work without compatibility issues on other (newer) OS X versions.