Re: [preprocessor] Dropping support for compilers that do not implement variadic macros

From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2020-09-15 10:01:18

On 2020-09-15 05:18, Edward Diener via Boost wrote:
> On 9/14/2020 7:38 PM, Andrey Semashev via Boost wrote:
>>
>> Boost.Preprocessor is used quite a lot throughout Boost, not in the 
>> least part specifically to support C++03. If it stops being C++03 
>> compatible, this will mean most of Boost will stop as well.
> 
> My proposed change does not mean that PP stops supporting C++03. Lots of 
> compilers supported variadic macros even when compiling in C++03 mode, 
> ie. gcc and clang and vc++ starting with VS2005 being the most 
> prominent. The few that actually did not support variadic macros in 
> C++03 mode should not be used with future Boost by anybody; they are 
> really ancient.

Ok, so it doesn't look as scary as it initially did. Thank you.

> Isn't that what discouraging compiling in C++03 mode is 
> all about, so that ancient compilers still supporting c++03 should not 
> be used by developers as Boost goes forward.

I actually don't know what the incentive to actively drop C++03 is.

(Disclosure: I write C++17 on a daily basis and I realize C++03 is 
limiting in some ways. It is not in others, and some written code can be 
made trivially compatible with C++03. Granted, this may not be the case 
with Boost.PP, but that code is already written and I suspect requires 
little maintenance. Also, in my C++17 code base I'm using some great 
C++03 libraries, including Boost, and I see nothing wrong about it. 
Please, don't consider this paragraph as an invitation to C++03 vs. 
C++11 argument.)