Lowers the priority of the current thread.

It's used by worker threads so that they use up the background CPU and do not stall the main thread. If the current thread is running with real-time priority, we decrease our priority by RTNICENESS. This is done in a portable way.

Otherwise, (we are running with the SCHED_OTHER policy) there's no portable way to set the nice level on the current thread. In Linux, it does work and it's the only one that is implemented as of now. In this case, the nice level is incremented on this thread by NICENESS.

Since :

3.0