04 信号量

import time
import random
from multiprocessing import Process,Semaphore

def f1(i,s):
    s.acquire()

    print('%s男嘉宾到了'%i)
    time.sleep(random.randint(1,3))
    s.release()

if __name__ == '__main__':
    s = Semaphore(4)  #计数器4,acquire一次减一,为0 ,其他人等待,release加1,
    for i in range(10):
        p = Process(target=f1,args=(i,s))

        p.start()