smart_ptr's yield_k and spinlock utilities can improve spinlock-based interprocess sychronization primitives

[Ion Gaztañaga]

See:

http://www.boost.org/doc/libs/1_52_0/boost/smart_ptr/detail/yield_k.hpp

and

http://www.boost.org/doc/libs/1_52_0/boost/smart_ptr/detail/spinlock.hpp

for internal thread-synchronization code that could be used to improve Interprocess spin-based synchronization primitives.

[Ion Gaztañaga]

The new method was added in Boost 1.55, in commit:

SVN: r85505 GIT:SHA-1: da01f2f69c4837ae283d8d06782b07aa32d8dca1

• Added a new spin-wait method. Spins + yields for a system tick and then sleeps a tick.

A new spin_wait class was developed:

http://www.boost.org/doc/libs/1_55_0/boost/interprocess/sync/spin/wait.hpp

This internal class tries to generalize spin_k and it's used in all spin-based synchronization primivitives.