atexit
— 退出处理程序
¶
The
atexit
模块定义用于注册和取消注册清理函数的函数。因此，会自动执行注册函数当解释器正常终止时。
atexit
运行这些函数按
reverse
次序当注册它们时；若注册
A
,
B
，和
C
，解释器终止时，运行它们将按次序
C
,
B
,
A
.
注意：
The functions registered via this module are not called when the program is killed by a signal not handled by Python, when a Python fatal internal error is detected, or when
os._exit()
被调用。
atexit.
register
(
func
,
*args
,
**kargs
)
¶
注册
func
as a function to be executed at termination. Any optional arguments that are to be passed to
func
must be passed as arguments to
register()
. It is possible to register the same function and arguments more than once.
At normal program termination (for instance, if
sys.exit()
is called or the main module’s execution completes), all functions registered are called in last in, first out order. The assumption is that lower level modules will normally be imported before higher level modules and thus must be cleaned up later.
If an exception is raised during execution of the exit handlers, a traceback is printed (unless
SystemExit
is raised) and the exception information is saved. After all exit handlers have had a chance to run the last exception to be raised is re-raised.
此函数返回 func ，从而可将其用作装饰器。
atexit.
unregister
(
func
)
¶
移除
func
from the list of functions to be run at interpreter shutdown. After calling
unregister()
,
func
is guaranteed not to be called when the interpreter shuts down, even if it was registered more than once.
unregister()
silently does nothing if
func
先前未注册。
另请参阅
atexit
范例
¶
以下简单范例演示导入模块时如何从文件初始化计数器，并在程序终止时自动保存计数器更新值 (终止时不依赖应用程序对此模块做出的明确调用)。
try: with open("counterfile") as infile: _count = int(infile.read()) except FileNotFoundError: _count = 0 def incrcounter(n): global _count _count = _count + n def savecounter(): with open("counterfile", "w") as outfile: outfile.write("%d" % _count) import atexit atexit.register(savecounter)
也可以把位置和关键词自变量传递给
register()
以沿注册函数传递当调用时：
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')
用作 装饰器 :
import atexit @atexit.register def goodbye(): print("You are now leaving the Python sector.")
这仅适用于可不带自变量调用的函数。