How to kill a pid [SOLVED]

[ebolisa]

Thanks for introducing me to multiprossesing. I finally got it working. Not sure if it's the best way of doing it but here's my final code.

import RPi.GPIO as GPIO
import time, os, signal, playsong
from multiprocessing import Process
from subprocess import check_output

buttonpin = 23 #GPIO23

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(buttonpin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

m_pid = 0

def play():
    '''play music from playsong.py '''
    playsong.song()

def get_pid():
    '''gets mplayer's actual pid'''
    global m_pid
    m_pid = int(check_output(["pidof","-s","mplayer"]))
    print "mplayer's pid: ", m_pid

def kill_pid(pid):
    '''used to kill mplayer's pid'''
    os.kill(pid, signal.SIGKILL)

def button():
    '''check if button is pressed'''
    while True:
        input_state = GPIO.input(buttonpin)
        if input_state == False:
            print 'on'
            time.sleep(0.3) #debounce
            kill_pid(m_pid)

if __name__ == '__main__':
  p1 = Process(target=play)
  p1.start()
  p2 = Process(target=button)
  p2.start()
  p3 = Process(target=get_pid)
  p3.start()
  p1.join()
  p2.join()
  p3.join()