# 6.12 `sched` -- Event scheduler

The `sched` module defines a class which implements a general purpose event scheduler:

class `scheduler`( | timefunc, delayfunc)

  The `scheduler` class defines a generic interface to scheduling events. It needs two functions to actually deal with the ``outside world'' -- timefunc should be callable without arguments, and return a number (the ``time'', in any units whatsoever). The delayfunc function should be callable with one argument, compatible with the output of timefunc, and should delay that many time units. delayfunc will also be called with the argument `0` after each event is run to allow other threads an opportunity to run in multi-threaded applications.

Example:

    >>> import sched, time
    >>> s=sched.scheduler(time.time, time.sleep)
    >>> def print_time(): print "From print_time", time.time()
    ...
    >>> def print_some_times():
    ...     print time.time()
    ...     s.enter(5, 1, print_time, ())
    ...     s.enter(10, 1, print_time, ())
    ...     s.run()
    ...     print time.time()
    ...
    >>> print_some_times()
    930343690.257
    From print_time 930343695.274
    From print_time 930343700.273
    930343700.276