The following simple example demonstrates how a module can initialize a counter from a file when it is imported and save the counter's updated value automatically when the program terminates without relying on the application making an explicit call into this module at termination.
try:
_count = int(open("/tmp/counter").read())
except IOError:
_count = 0
def incrcounter(n):
global _count
_count = _count + n
def savecounter():
open("/tmp/counter", "w").write("%d" % _count)
import atexit
atexit.register(savecounter)
Positional and keyword arguments may also be passed to register() to be passed along to the registered function when it is called:
def goodbye(name, adjective): print 'Goodbye, %s, it was %s to meet you.' % (name, adjective) import atexit atexit.register(goodbye, 'Donny', 'nice') # or: atexit.register(goodbye, adjective='nice', name='Donny')