John Maddock <john <at> johnmaddock.co.uk> writes:
Anthony Williams wrote:
Since the boost thread headers can now be used without including <windows.h>, can I commit the following patch to boost/config/suffix.hpp in order to stop BOOST_DISABLE_THREADS being defined just because the user specified /Za on the command line?
There was a discussion about this back in May, but I don't remember there being a definite outcome.
That would almost certainly break Regex and maybe other libraries as well
Why? The only uses of BOOST_DISABLE_THREADS that I can see are in the smart_ptr detail headers and in xpressive. In neither case will the code break if this is not defined on a multi-threaded build, but /Za is specified. There's more uses of BOOST_HAS_THREADS, but looking at them (including those in the regex headers), it seems to me that BOOST_HAS_THREADS really ought to be defined for a multi-threaded build, even if /Za is specified, otherwise the code won't be thread-safe. Code that depends on <windows.h> will break if /Za is specified, but that's a separate issue to BOOST_DISABLE_THREADS. I'm not suggesting we should be able to *build* boost with /Za, just use it.
I would prefer not to make this change to Boost.Config for 1.35, but we should try to find a decent way of handling this.
I was thinking that we didn't fix this in 1.34, so we ought to try and fix it in 1.35. Anthony