----- Original Message -----
> On 07/11/2013 10:41 AM, clin...@elemtech.com wrote:
> > They also appear similar to me, so I would start with the
> > assumption that they should be unified.
>
> I just dug into this a bit.
>
> One difference is that CMAKE_OSX_SYSROOT can be set to a logical
> SDK name rather than a path. In Darwin.cmake there is code to
> transform it to a path by running
>
> xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
>
> If we unify the two we will need to find a way to handle this.
>
> The value of CMAKE_OSX_SYSROOT is not used in any CMake modules
> outside of Darwin.cmake (and an old reference in Darwin-icc.cmake
> that should probably be refactored anyway). It is used in only
> three C++ sources:
>
> * cmCoreTryCompile.cxx: The value of CMAKE_OSX_SYSROOT is passed
> into the build of the test project for a try-compile. This
> will probably be needed for CMAKE_SYSROOT too.
>
> * cmGlobalXCodeGenerator.cxx: The value of CMAKE_OSX_SYSROOT is
> used to set the generated Xcode SDKROOT attribute. The SDKROOT
> can be a logical name or a path but IIUC the logical name is
> preferred. Xcode uses it to add the -isysroot flag.
>
> * cmLocalGenerator.cxx: The value of CMAKE_OSX_SYSROOT is used
> to add the -isysroot flags for generators besides Xcode (since
> Xcode uses the SDKROOT attribute).
>
> It looks to me like CMAKE_SYSROOT and CMAKE_OSX_SYSROOT are
> pretty much identical other than the logical name mapping.
> At a minimum we need to make them mutually exclusive (at most
> one can be set in a single build tree). Ideally we should
> combine them so that one only needs to set CMAKE_SYSROOT on
> any platform.
>
> Combining them is safe only if we're sure CMAKE_SYSROOT will
> not be used for anything besides the toolchain system SDK.
>
I'm seeing slight hints that we should not merge them.
$ xcrun --help
...
--sdk <sdk name> find the tool for the given SDK name
--toolchain <name> find the tool for the given toolchain
...
I currently have SDKs are under
/Applications/Xcode.app/Contents/Developer/Platform
- 10.7, 10.8, iPhoneOS6.1, iPhoneSimulator6.1
and toolchains found under /Applications/Xcode.app/Contents/Developer/Toolchains
- XcodeDefault.xctoolchain (clang)
There's also the llvm/gcc in another place: /usr/llvm-gcc-4.2.
I'm also seeing some C/C++ includes under both the toolchain and SDK trees.
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/4.2/include/stdint.h
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/usr/include/stdint.h
The toolchain version of stdint.h includes the use of __STDC_HOSTED__, if that
means anything here.
http://tigcc.ticalc.org/doc/cpp.html#SEC15_STDC_HOSTED
What do you think Brad? Does it hint towards not merging them?
Clint
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