"""Test affinity only on this short-lived Python worker thread."""
import ctypes as c
from ctypes import wintypes as w
import json
import threading
k=c.WinDLL("kernel32",use_last_error=True)
k.GetCurrentThread.restype=w.HANDLE
k.GetCurrentProcess.restype=w.HANDLE
k.GetProcessAffinityMask.argtypes=[w.HANDLE,c.POINTER(c.c_size_t),c.POINTER(c.c_size_t)]
k.SetThreadAffinityMask.argtypes=[w.HANDLE,c.c_size_t]
k.SetThreadAffinityMask.restype=c.c_size_t
def worker():
    pm,sm=c.c_size_t(),c.c_size_t()
    k.GetProcessAffinityMask(k.GetCurrentProcess(),c.byref(pm),c.byref(sm))
    print(json.dumps({"process_mask":hex(pm.value),"system_mask":hex(sm.value)}))
    for mask in [1,2,3,4,8,0xc,0xf,0xfc,0xfff,0xffffc,0xfffff,0xfffffffc]:
        c.set_last_error(0)
        old=k.SetThreadAffinityMask(k.GetCurrentThread(),mask)
        error=c.get_last_error()
        print(json.dumps({"requested":hex(mask),"previous":hex(old),"error":error}))
        if old:
            if not k.SetThreadAffinityMask(k.GetCurrentThread(),old):
                raise c.WinError(c.get_last_error())
t=threading.Thread(target=worker)
t.start()
t.join()