#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2022/08/13 20:29:30 +0900>
"""
Python + Mutex sample. Windows only. by using ctypes.

Windows10 x64 21H2 + Python 3.9.13 64bit
"""

import ctypes
import time

MUTEXNAME = "python_mutex_sample_02"


def main():
    knl32 = ctypes.windll.Kernel32
    mtx = knl32.CreateMutexA(0, 1, MUTEXNAME)
    result = knl32.WaitForSingleObject(mtx, 0)
    if result != 0:
        print("%s already exists" % MUTEXNAME)
    else:
        print("New process.")
        for i in range(10):
            print(i)
            time.sleep(1)

    knl32.ReleaseMutex(mtx)
    knl32.CloseHandle(mtx)


if __name__ == '__main__':
    main()