import sys
import threading

class myclass(object):
  def __init__(self, oldstdout):
    self._global_write_lock = threading.Lock()
    self._output = oldstdout

  def __getattr__(self, attr):
    if attr == "write":
      return self.write

    return getattr(self._output, attr)

  def write(self, *args):
    self._global_write_lock.acquire()
    self._output.write(*args)
    self._global_write_lock.release()

sys.stdout = myclass(sys.stdout)

print "Hello, world!"