Re: [boost] [config] Macro proposal

From: David Abrahams (dave_at_[hidden])
Date: 2006-06-14 17:39:09

Rene Rivera <grafik.list_at_[hidden]> writes:

> Gennaro Prota wrote:
>> Hi guys,
>> 
>> could we please add something like this to the config system?
>> 
>>  #if defined(__GNUC_PATCHLEVEL__)
>>  # define <choose_a_name> ( __GNUC__ * 10000               \
>>                                    + __GNUC_MINOR__ * 100  \
>>                                    + __GNUC_PATCHLEVEL__ )
>>  #else
>>  # define <choose_a_name> ( __GNUC__ * 10000               \
>>                                   + __GNUC_MINOR__ * 100)
>>  #endif
>> 
>> PS: of course it's possible to "share" the common part of the
>> replacement-lists:
>> 
>>  ( __GNUC__ * 10000 + __GNUC_MINOR__ * 100)
>> 
>> or
>> 
>>  (100 * ( __GNUC__ * 100 + __GNUC_MINOR__))
>> 
>> 
>> The decision is up to John :)
>
> I've been working on making such changes for some time now 
> <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?BoostConfig>. 
> But it's very slow going as I have almost no free time.

This is great and very complete. It looks like you've worked things
out so completely that actually doing the coding should be pretty
easy.

There is one nit:

> Some compilers, like Comeau C++, try and simulate other
> compilers. For them it is possible that some workarounds are
> dependent on the particular version of the compiler they are
> emulating. Here's some of those issues, as they come up:
> 
>     * boost/config/compiler/comeau.hpp - It emulates VC, and has the
>       _MSC_VER define.
>
>     * boost/config/compiler/intel.hpp - It emulates VC, and has the
>       _MSC_VER define.  
> 
> The only option I can think of is to go ahead and define the
> corresponding version macro and have the code deal with the multiple
> defs.

If I understand what you're suggesting correctly, I don't think that
part is a very good idea, because the status quo is that Boost
libraries expect BOOST_MSVC only to be defined when it really _is_
MSVC, and we go to some lengths to ensure it.  I don't mind the idea
of 

   BOOST_CXX_EMULATED_MSVC

or

   BOOST_CXX_MSC_VER

though.

 -- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com