Building on Mac with --enable-tls

[Tom N]

> On March 18, 2020 at 7:53 PM Iain Sandoe <idsandoe@googlemail.com> wrote:
> 
> Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
> > 
> > I would expect the default to be correct for the target i.e.--disable-tls. If enabling it worked correctly, it would be the default.
> > That makes no sense, neither std::mutex nor std::unique_lock uses TLS.
> 
> Darwin uses emulated TLS on all versions (powerpc, i686, x86_64) the correct default (to use emulatedTLS) is selected without requiring any additional configure options. Selecting --enable-tls will undoubtedly produce an invalid configuration.
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52268 is an enhancement PR to add native TLS for 10.7+ (but that would still not work on earlier versions, of course).

Thank you both for the quick responses!  Knowing that lack of --enable-tls is normal on Mac set me in the right direction.  The synchronization problem was due to an equally bad assumption.  All working as expected now.

Thanks again!