https://manpages.ubuntu.com/manpages/xenial/man3/pthread_mutexattr_setprotocol.3posix.html
Ubuntu Manpage: pthread_mutexattr_setprotocol - set the protocol attribute of the mutex attributes...
set the protocol attribute of the mutex attributes object (REALTIME THREADS)
https://cygwin.com/pipermail/cygwin/2004-May/117368.html
pthread_mutexattr_setpshared supported?
pthreadsupported