[cmake-developers] Suspicious Clang versions

[Brad King]

On 08/05/2013 09:26 AM, Stephen Kelly wrote:
> Brad King wrote:
>> We need to fix this somehow or CMAKE_*_COMPILER_VERSION will be
>> useless for Clang.  Sean, is there any way to extract the underlying
>> Clang version, perhaps with different preprocessor macros?  We at
>> least need to be able to detect which version scheme is in use so
>> we can report it somehow.

According to

 https://developer.apple.com/library/mac/#documentation/porting/conceptual/portingunix/compiling/compiling.html

and local testing we can use __APPLE_CC__ to detect Apple compiler
builds.

> This might lead to a solution:
> 
>  https://github.com/mozilla/rust/issues/6419

That shows a difference in the version string reported from the
compiler but AFAICT there is no way to determine the "based on"
version from the preprocessor.

Also any preprocessor tests in C/C++ code that use __clang_major__
for anything will get incorrect results.  It would have to be
first conditioned on __APPLE_CC__ to know how to interpret the
version number.

We could consider treating this as a separate compiler and using
a new compiler id like ClangApple or AppleClang or something.

-Brad