How to exit from thread_pool_start () ?

How to exit from thread_pool_start () ?

If I do thread_pool_create () with flags:
#define POOL_FLAG_EXIT_SELF 0x00000001
#define POOL_FLAG_USE_SELF 0x00000002
thread_pool_start () doesn’t return;

I’ve found (in dispatch.h) additional constants:
#define POOL_FLAG_EXITING 0x00000004
#define POOL_FLAG_CHANGING 0x00000008,
but I can’t find what they mean;

what happens when I start thread with flag(s):

why you want to exit from thread pool!!

I think you can also put the process into background, and then continue.