copytree with timeout in windows

[Astan Chee]

Hi,
I'm trying to modify the copytree function in shutil so that any file 
being copied does not take more than 5 minutes (if it does, skip to the 
next one). This is what I have so far:

import shutil
import signal, os

def handler(signum, frame):
    print 'Signal handler called with signal', signum
    raise IOError, "Couldn't open device!"

signal.signal(signal.SIGALRM, handler)

def copytree(src, dst):
    names = os.listdir(src)
    os.makedirs(dst)
    signal.alarm(0)
    for name in names:
        if name in ignored_names:
            continue
        srcname = os.path.join(src, name)
        dstname = os.path.join(dst, name)
        try:
            if os.path.isdir(srcname):
                copytree(srcname, dstname, symlinks, ignore)
            else:
                signal.alarm(300)
                shutil.copy2(srcname, dstname)
        except (IOError, os.error), why:
            print str(why)
        # catch the Error from the recursive copytree so that we can
        # continue with other files
        except Error, err:
            print str(err.args[0])

source = "c:\\testwa\\"
destination = "d:\\testwa\\"

copytree(source,destination)

Then I re-read the documentation which said that signal.SIGALRM is 
unix/linux only. How do I go about doing this in windows?
Thanks for any help.
Cheers
Astan