How can I reliably detect the version of clang at preprocessing time?

Question

Apparently, the clang bundled with Xcode doesn\'t respect the upstream __clang_major__ and __clang_minor__ values, and instead reports an Xcode use

Answer 1

If the feature checking macros don't cover what you need to check for then you do need to treat vendor releases separately as they may have very different content from the open source LLVM releases. You can use __apple_build_version__ to check for a specific Apple LLVM version.