The AtExit module provides ANSI-C style exit processing modeled after
the atexit function in the standard C library (see atexit(3C)).  Various
exit processing routines may be registered by calling atexit and passing
it the desired subroutine along with any desired arguments.  Then, at
program-exit time, the subroutines registered with atexit are invoked
with their given arguments in the reverse order of registration (last
one registered is invoked first).  Registering the same subroutine more
than once will cause that subroutine to be invoked once for each
registration.