A synchronization library of mutex functions and condition variable functions for threads which are compatible with pthread library functions conforming to a (POSIX) standard. The library can utilize a mutex data structure and a condition variable data structure both including lockwords and queuing anchors. In the library, Compare Swap (CS) instruction processing can be used to protect shared resource. The synchronization library can support priority queuing of threads and can have an ability to yield control when CS spin lock iterations exceed a set limit.