Re: [boost] [Predef] Pre-review comments

Subject: Re: [boost] [Predef] Pre-review comments
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2012-02-28 17:24:09

On 02/28/2012 07:06 AM, Rene Rivera wrote:

> In other words.. We need to make a distinction between the *actual*
> compiler vs. the *compatible/emulated* compiler. There are obviously
> three options to this:

I don't think that's a good idea.

Just do

#if defined(__clang__)
   frontend is clang
#elif ...
....
#elif defined(__GNUC__)
   frontend is GCC
#elif ...
...
#endif

The whole mechanism to detect what the frontend is should be a chain of 
if/elif in a single file.

I thought this much was a given. This is how Boost.Config and 
Boost.Detect work.

> 1. Make the default/base/undecorated definitions reflect the *actual*
> compiler. And add a set of predefs for the *emulated* compiler.
>
> 2. Make two different parallel sets of definitions, one for *actual* and
> one for *emulated*.
>
> 3. Make the default/base/undecorated definitions reflect the *emulated*
> compiler. And add a set for the *actual* compiler.

This looks like it would be very hard to maintain and hard to ensure 
that it is correct.

It also assumes that all compilers that emulate other compilers do it in 
an uniform way.