[boost] shared_ptr and BOOST_DISABLE_THREADS

From: Carl Daniel (cpdaniel_at_[hidden])
Date: 2004-04-21 22:22:54

Playing with a Spirit-based parser for a simple scripting language I noticed
that #defining BOOST_DISABLE_THREADS resulted in a parser that was nearly 3
times faster.   For reasons that aren't relevant to the discussion, this had
to be an MT build, but the parser didn't need thread safety.

That made me wonder though:  If I #define BOOST_DISABLE_THREADS in some
translation units but not in others, what's going to happen?  I suppose one
way of summarizing it is this:  does BOOST_DISABLE_THREADS change the type
of shared_ptr that's made?  If not, that seems like a rather serious problem
to me - especially given the enormous difference in performance that I
measured  (optimized build with VC8 alpha).

What obvious thing am I overlooking?

-cd