python如何使用ctrl+c来退出程序？

网上找到两种方法，哪个比较好，比较不浪费CPU,因为都使用上了无限的循环，
#-*- coding: utf-8 -*-
import signal,time,sys
def exit():
def myhandle(signalNum,e):
# print 'signalNum : %s' % (signalNum)
# print 'e : %s' % (e)
sys.exit(0)
signal.signal(signal.SIGINT, myhandle)
signal.signal(signal.SIGTERM, myhandle)
while True:
time.sleep(1)
def exit_1 ():
while True:
try:
INPUT=raw_input()
except KeyboardInterrupt :
sys.exit(0)
break
except EOFError:
print 'Unknown End of file!'
continue
if __name__ == "__main__":
exit()
#or exit_1()