Re: [boost] [config] BOOST_DISABLE_THREADS defined by Boost.Config

From: Joe Gottman (jgottman_at_[hidden])
Date: 2008-04-03 19:35:32

Peter Dimov wrote:
> Joe Gottman quite correctly points out in
> 
> http://svn.boost.org/trac/boost/ticket/1762
> 
> that shared_ptr should honor user definitions of BOOST_DISABLE_THREADS and 
> disable MT support.
> 
> Unfortunately, despite documenting quite clearly that BOOST_DISABLE_THREADS 
> is a user macro, Boost.Config defines it in some situations. This means that 
> I can't rely on this macro to reflect the user's intent, as I don't know 
> whether it's been set explicitly by the user, or implicitly (and incorrectly 
> IMO) by Boost.Config.
> 
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> 

    The code in suffix.hpp looks like

#if defined(BOOST_DISABLE_WIN32) && defined(_WIN32) \
    && !defined(BOOST_DISABLE_THREADS) && !defined(BOOST_HAS_PTHREADS)
#  define BOOST_DISABLE_THREADS
#endif

As far as I can tell, the purpose of this is to disable threading if 
Windows is disabled and there is no other threading system available.  I 
think we can get the same result in a much clearer fashion without 
touching BOOST_DISABLE_THREADS by the following:

#if defined(BOOST_DISABLE_WIN32) && defined(_WIN32)
#  undef BOOST_HAS_WINTHREADS
#endif

Joe Gottman