Andrey Semashev wrote:

On Fri, Feb 28, 2014 at 8:00 PM, Peter Dimov wrote:

...

Does anyone know what is the earlier version of Clang that supports the __sync_* intrinsics?

I don't know what was the earliest one but you could use __has_builtin macro to check for its presence.

Yes, I figured that out slightly after I sent the mail. Version checks are not the Clang way and are a symptom of an outdated mentality. :-)

You can also use __GCC_HAVE_SYNC_COMPARE_AND_SWAP_N macros...

Interestingly, it turns out that I already do that. The problem prompting https://svn.boost.org/trac/boost/ticket/9315 is probably that an earlier #ifdef path is taken instead.