Building clang/cling 3.5 for ROOT on Lion

Chris Jones jonesc at
Tue Apr 8 02:26:43 PDT 2014


On 08/04/14 10:14, Mojca Miklavec wrote:
> On Tue, Apr 8, 2014 at 10:12 AM, Chris Jones wrote:
>>>> Indeed. They aren't quite the same thing though in the end, as on OSX
>>>> 10.8 and newer it supports c++11, whereas on 10.7 it doesn't, because of the
>>>> underlying system support. So the same clang34 compiler now builds root6
>>>> fine on OSX10.9, but fails on 10.7.
>>>> My recollection of all the previous times c++11 has been discussed, can
>>>> be summarised as there is no obvious way to support it cleanly on older OSX
>>>> releases. So if an upstream package, as ROOT6 has, is actively only
>>>> targetting c++11 supporting compilers, then effectively these ports cannot
>>>> be used on older OSX releases now. Is that correct, or am I being overly
>>>> pessimistic here ?
>>> Using latest gcc (currently gcc48) might be a way to support C++11 on OS X
>>> < 10.9, but otherwise, with clang, C++11 requires 10.9+.
>> Yes, I thought of that. But as I understanding it mixing libc++ and
>> libstdc++ runtimes is an absolute no no when c++11 is involved, so the user
>> would have to update their MacPorts settings to build *everything* with
>> gcc(48) ?
> So would it work in theory if ROOT could be compiled without any
> external dependencies (other than Cocoa)? And is compiling it "without
> external dependencies" (and with some limited functionality) feasible
> at all?

Not really within MacPorts. root in macports is designed to use various 
macports provided dependencies. Thats the benefit of using MacPorts...

First try installing MacPorts gcc48, then use it to build root6 
standalone, outside macports, without it finding any of Macports 
libraries (so move /local/local out the way for a while). If that works, 
you could try try building inside macports, but you will have to first 
mac sure to build *every* dependency root needs with gcc48 as well, 
instead of the normal default compiler.

Honestly, this to me sounds like a lot of effort. I personally would be 
more inclined to invest that amount of effort in updating my system to 
10.9. Ultimately, this is the only way to get a system that properly 
supports c++11...

> I checked and it seems that it's depending on CoreFoundation which
> depends on /usr/lib/libobjc.A.dylib, no libstdc++ (but OpenGL depends
> on /usr/lib/libstdc++.6.dylib and that's probably needed).
> Btw: what's the trick to make fortran-based libraries depend on
> /usr/lib/libstdc++.6.dylib in the current port (rather than on
> /opt/local/lib/libgcc/libgcc_s.1.dylib)?

Fortran libraries do not need a C++ runtime at all ... If a library that 
contains fortran symbols is linking against a c++ runtime, it must be 
because it also contains C++ symbols.


> Mojca

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