CentOS 7 - Updates for x86_64: system environment/libraries: pth
pth - The GNU Portable Threads library
Pth is a very portable POSIX/ANSI-C based library for Unix platforms
which provides non-preemptive priority-based scheduling for multiple
threads of execution ("multithreading") inside server applications.
All threads run in the same address space of the server application,
but each thread has it's own individual program-counter, run-time
stack, signal mask and errno variable.