A simple program demonstrating race condition

dem_race_condition.py

import threading

#define a global variable
some_var = 0

class IncrementThread(threading.Thread):
    def run(self):
        #we want to read a global variable
        #and then increment it
        global some_var
        b = some_var
        print "some_var in %s is %d" % (self.name, b)
        some_var = b + 1
        print "some_var in %s after increment is %d" % (self.name, some_var)

if __name__ == "__main__":
    for i in range(10):
        t = IncrementThread()
        t.start()