Re: [Boost-users] undefined reference to `__sync_fetch_and_add_4'

Birju Prajapati wrote:

I figured it out.

It was an obscure, seemingly undocumented option to bjam:

instruction-set=i686

You make it sound as if something in Boost.Build is not working and requires to specify this option. Can you explain why things were not working without that option? Note that all it does is add -march=i686 - Volodya