[SG10] __has_[cpp_]attribute

Stephen Kelly steveire at gmail.com
Sun Jun 15 08:56:05 CEST 2014


Stephen Kelly wrote:

> Richard Smith wrote:
> 
>>  1) That's a *lot* of macros. We might be able to get away with the cost
>>  of
>> the number of macros that SG10 is currently proposing, but I would be
>> *seriously* concerned about a measurable performance cost (on compiling
>> an empty file, which is not actually an irrelevant concern) of
>> predefining hundreds of __has_attribute macros.
>> 
>>  2) Either of those identifiers could contain underscores, and there is
>>  no
>> other separator character that works.
>> 
>> [3) It's ugly.]
> 
> Good points.
> 

Here's something I didn't expect: User libraries defining the __foo macros 
themselves:

 https://codereview.qt-project.org/#/c/87474/1//ALL,unified

Should that be encouraged or discouraged?

Thanks,

Steve.


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