Is there any small library, that wrapps various processors' CAS-like operations into macros or functions, that are portable across multiple compilers?
PS. The atomic.hpp library is inside boost::interprocess::detail namespace. The author refuses to make it a public, well maintained library.
Lets reopen the question, and see if there are any other options?
Intel Threading Building Blocks has a nice portable atomic<T> template which does what you want. But whether it is a small library or not can of course be debated..