[cmake-developers] C++11 and target_compiler_feature proposal

[Stephen Kelly]

Brad King wrote:

> On 10/21/2013 04:05 PM, Stephen Kelly wrote:
>> I'm still not sure that generating a header specific to the compiler (ID
>> and version) is a good idea.
> [snip]
>> So, I think maybe it would make sense to list features separately, and if
>> someone does this:
> 
> I thought we had reached that conclusion before.  See the bottom of
> this message:
> 
>  
http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/6726/focus=7809
> 
> Anyway, we agree.

Further-on, you responded:

> Why do you need to check features of a compiler not currently enabled?

> 
>>  write_compiler_detection_header(
>>    FILE ${CMAKE_CURRENT_BINARY_DIR}/grantlee_compiler_detection.h
>>    PREFIX Grantlee_
>>    FEATURES cxx_final cxx_override
>>  )
> 
> Yes, though it still needs the mandatory VERSION.

I thought the VERSION would be optional and would default to 
CMAKE_MINIMUM_REQUIRED_VERSION:

 http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/6726/focus=7812

> 
>> the generated header would look something like this:
> 
> Yes.
> 
> Actually it appears this header will duplicate most of the compiler
> feature
> knowledge encoded in the CMake platform modules we discussed before.  I
> wonder if we can come up with a representation that can be used to
> generate both.

Probably. However, that means that we either shouldn't use the clang 
__has_feature() test that I implemented, or we'll have to duplicate all of 
that information anyway.

Thanks,

Steve.