[cfe-dev] getting clang to find non-default libstdc++

[Nathan Ridge]

>  > > I am trying to use clang for the first time, on Ubuntu 10.04. 
>  > > 
>  > > The default compiler on Ubuntu 10.04 is GCC 4.4, but I've built 
>  > > GCC 4.7 from source and use it to compile C++11 programs. 
>  > > 
>  > > Clang finds GCC 4.4's libstdc++ no problem, but I need it to 
>  > > use GCC 4.7's libstdc++ because my program uses standard 
>  > > library features that have been added between GCC 4.4 and 4.7. 
>  > > How do I direct clang to find the 4.7 libstdc++? 
>  > > 
>  > > I saw the following instructions on the "Get Started" page: 
>  > > 
>  > > "If Clang cannot find your system libstdc++ headers, please 
>  > > follow these instructions: 
>  > >  - 'gcc -v -x c++ /dev/null -fsyntax-only' to get the 
>  > >    path. 
>  > >  - Look for the comment "FIXME: temporary hack: 
>  > >    hard-coded paths" in clang/lib/Frontend/InitHeaderSearch.cpp 
>  > >    and change the lines below to include that path" 
>  > > 
>  > > Is that the only way? Having to recompile the compiler to get 
>  > > it to find a different standard library seems a bit excessive... 
>  > > shouldn't one be able to switch standard libraries without 
>  > > recompiling the compiler? 
>  > 
>  > Those comments are a bit out of date for linux. You should be able to 
>  > configure clang with --with-gcc-toolchain pointing to where you 
>  > install g++ 4.7. 
>  
> Thanks! I think the webpage should be updated to reflect this. 
> I attached a patch. 
>  
> Can you mention that in general, Clang should automatically detect the  
> best version of libstdc++ headers available and use them, and that it  
> will look both for system installations of libstdc++ as well as  
> installations adjacent to clang itself? 
>  
> The --with-gcc-toolchain should really be a fallback for when the  
> configuration is quite strange. 

You callin' my configuration strange? ;) 

Updated patch is attached.

Regards,
Nate
 		 	   		  
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