The debugger tracks the current thread using the debugger variable,
$thread. You can use this variable in print commands or in expressions. Threads are displayed in the Debug Control view with a unique ID that is
used by the debugger and a unique ID from the Operating System (OS) :
os_idle_demon #3 stopped (PID 255 was running)
#3 is the unique ID used by the
PID 255 is the ID from the OS.
A separate call stack is maintained for each thread and the selected stack frame is shown in bold text. All the views in the DS-5 Debug perspective are associated with the selected stack frame and are updated when you select another frame.
Figure 6-1 Threading call stacks in the Debug Control view