enum QosClass
{
case Pcntl::Background
; //
Runs the process after all high-priority ones had ran their courses.
case Pcntl::Default
; //
Runs the process after all high-priority processes but before the low-priority ones.
case Pcntl::UserInteractive
; //
Runs the process as the highest priority level.
case Pcntl::UserInitiated
; //
Runs the process at high priority level but below Pcntl::UserInteractive ones.
}