[boost] [detail/lightweight_mutex] Win32 threading selection in boost/detail/lightweight_mutex.hpp

Subject: [boost] [detail/lightweight_mutex] Win32 threading selection in boost/detail/lightweight_mutex.hpp
From: joaquin_at_[hidden]
Date: 2008-12-16 05:09:50

Hello,

This is a followup of a discussion we had some time ago:

http://lists.boost.org/Archives/boost/2007/09/127115.php

Lines 31-40 of boost/detail/lightweight_mutex.hpp read like this:

#if !defined(BOOST_HAS_THREADS)
# include <boost/detail/lwm_nop.hpp>
#elif defined(BOOST_HAS_PTHREADS)
#  include <boost/detail/lwm_pthreads.hpp>
#elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
#  include <boost/detail/lwm_win32_cs.hpp>
#else
// Use #define BOOST_DISABLE_THREADS to avoid the error
#  error Unrecognized threading platform
#endif

I think the conditions for selecting boost/detail/lwm_win32_cs.hpp are
suboptimal because they're ruling out the case where the user's disabled
Pthreads in cygwin/mingw by explicitly defining BOOST_HAS_WINTHREADS,
a case covered by boost/config/platform/cygwin.hpp: in such a situation, 
Win32
threading is available but none of WIN32 and similar are defined by default
(unless <windows.h> has been previously included, which makes
boost/detail/lightweight_mutex.hpp context dependent).
Wouldn't it be better to change the selection code to the following?

#elif defined(BOOST_HAS_WINTHREADS)
#  include <boost/detail/lwm_win32_cs.hpp>
#else

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo