#!/usr/bin/env python
from __future__ import with_statement
import os, cPickle
def run_in_separate_process(func, *args, **kwds):
  pread, pwrite = os.pipe()
  pid = os.fork()
  if pid > 0:
    os.close(pwrite)
    with os.fdopen(pread, 'rb') as f:
      status, result = cPickle.load(f)
    os.waitpid(pid, 0)
    if status == 0:
      return result
    else:
      raise result
  else: 
    os.close(pread)
    try:
      result = func(*args, **kwds)
      status = 0
    except Exception, exc:
      result = exc
      status = 1
    with os.fdopen(pwrite, 'wb') as f:
      try:
        cPickle.dump((status,result), f, cPickle.HIGHEST_PROTOCOL)
      except cPickle.PicklingError, exc:
        cPickle.dump((2,exc), f, cPickle.HIGHEST_PROTOCOL)
    os._exit(0)
#an example of use
def treble(x):
  return 3 * x
def main():
  #calling directly
  print treble(4)
  #calling in separate process
  print run_in_separate_process(treble, 4)