[cfe-dev] Problems with -stdlib=libc++

[Douglas Gregor]

On Aug 20, 2012, at 5:55 AM, Michael Lehn <michael.lehn at uni-ulm.de> wrote:

>> On Mon, Aug 20, 2012 at 4:48 AM, Michael Lehn <michael.lehn at uni-ulm.de> wrote:
>>> Im sitting here in front of a new iMac:
>>> (a)  I installed the latest XCode and its command line tool.
>>> (b)  I also installed clang-3.1 and clang-3.2 from MacPorts.
>>> 
>>> Now I can not compile a simple program "main.cc" like
>>> 
>>> -----------------------
>>> #include <complex>
>>> #include <type_traits>
>>> int main() {}
>>> -----------------------
>>> 
>>> neither
>>> (1)     clang++ -std=c++11 -std=libc++ main.cc
>>> nor
>>> (2)     clang++ -std=c++11 main.cc
>>> work.  In (1) 'complex' can not be found; in (2) 'type_traits' can
>>> not be found.
>>> 
>>> I guess this is a configuration problem.  On other machines with an
>>> older XCode and older MacPorts and older ... everything is fine. But
>>> maybe there is somebody out there who had the same problem recently.
>>> At the moment I don't know where I should start to track down the
>>> problem.
>> 
>> First: which clang++ are you running?
>> 
>> On this machine I see
>> $ which clang++
>> /usr/bin/clang++
>> $ clang++ -v
>> Apple clang version 4.0 (tags/Apple/clang-421.0.57) (based on LLVM 3.1svn)
>> Target: x86_64-apple-darwin12.0.0
>> Thread model: posix
>> 
>> after installing just the XCode command line tools (nothing from
>> MacPorts), and while
>> 
>> $ clang++ -std=c++11 small.cc
>> small.cc:2:10: fatal error: 'type_traits' file not found
>> #include <type_traits>
>>        ^
>> 1 error generated.
>> 
>> fails, with -stdlib=libc++ the command
>> 
>> $ clang++ -std=c++11 -stdlib=libc++ small.cc
>> $ ./a.out
>> 
>> works as expected.
>> 
>> -- James
> 
> Thanks James,
> 
> clang from Xcode works.  But selecting any clang variant from MacPorts fails!

MacPorts needs to start installing libc++ headers relative to the clang binaries it installs; they can look at where those headers land in an Xcode-installed Clang.

	- Doug