On 25 September 2016 at 22:21, Chris Jones <[email protected]> wrote:
> > > > On 25 Sep 2016, at 2:49 pm, Yongwei Wu <[email protected]> wrote: > > > > On 25 September 2016 at 21:35, Chris Jones <[email protected]> > wrote: > >> >> >> On 25 Sep 2016, at 2:25 pm, Brandon Allbery <[email protected]> wrote: >> >> >> On Sun, Sep 25, 2016 at 8:29 AM, Ken Cunningham < >> [email protected]> 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.) > > > Its exactly the same situation as with libc++ v libstdc++. There are ways > it can be ok and ways you can run into problems. The only guaranteed way (I > know of) to not have issues is not to do it. > My point is that a well-designed application/library should not do this. And if it did it, problems might have occurred long ago (esp. on Windows, supposing a Windows port exists). If things are going on well so far, we probably do not need to worry much. At least I do not see what we can do to help the case at the moment. -- Yongwei Wu URL: http://wyw.dcweb.cn/
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