LibCxxOnOlderSystems - and more software that is pushing for gcc

Yongwei Wu wuyongwei at gmail.com
Sun Sep 25 06:49:03 PDT 2016


On 25 September 2016 at 21:35, Chris Jones <jonesc at hep.phy.cam.ac.uk> wrote:

>
>
> On 25 Sep 2016, at 2:25 pm, Brandon Allbery <allbery.b at gmail.com> wrote:
>
>
> On Sun, Sep 25, 2016 at 8:29 AM, Ken Cunningham <
> ken.cunningham.webuse at gmail.com> wrote:
>
>> What is happening exactly on my MacPros running 10.11, I wonder? Software
>> installed by macports on 10.11 is using clang++ (mostly) and g++
>> (sometimes). clang++ is linking against libc++, and g++ is presumably
>>  linking against libstdc++ as that is what it does -- yet there appear to
>> be no visible issues...and these libraries find each other.
>
>
> An additional complication is that it's not using the same libstdc++: it's
> using the GPL3 one with C++11 support, not Apple's GPL2/pre-C++11 one. So
> potentially the clash here is between the two libstdc++ versions, not
> libstdc++ and libc++.
>
>
> Indeed, mixing two different libstdc++ runtimes has the same sort of
> issues as mixing libstd++ with libc++.
>

I actually do not think this is normally an issue. If the dynamic
libraries​ manage the lifetime of their own object, i.e. do not do
something like creating an object in a library but not providing a function
to destroy it (so that the application needs to delete it), bad things
should not occur. At least that is the only case I am aware of. (I
encountered this kind of problems on Windows, which was even worse, as each
new release of MSVC brought in a different C/C++ runtime, which can also be
either static or dynamic.)

-- 
Yongwei Wu
URL: http://wyw.dcweb.cn/
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