Question

I searchedon internet and learned other method of implementing it
the problem now i have found out. my execution time always becomes more than that
of time out if i write stdout=subprocess.PIPE in subprocess.Popen. If i am removing it then it is taking normal execution time

import subprocess, datetime, os, time, signal
//setting time for timeout
timeout=3
start = datetime.datetime.now()
process = subprocess.Popen(["python", "/home/bourne/untitled.py"],shell=False, stdout=subprocess.PIPE,stderr=subprocess.PIPE)
while process.poll() is None:
        time.sleep(0.1)
        now = datetime.datetime.now()
        if (now - start).seconds > timeout:
            os.kill(process.pid, signal.SIGKILL)
            os.waitpid(-1, os.WNOHANG)
            print "error"       
            print (now - start).seconds
            break
        print (now - start).seconds

Answer 1

I have successfully solved the problem. the solution is 

import subprocess, signal, os, threading, errno
from contextlib import contextmanager

class TimeoutThread(object):
    def __init__(self, seconds):
        self.seconds = seconds
        self.cond = threading.Condition()
        self.cancelled = False
        self.thread = threading.Thread(target=self._wait)

    def run(self):
        """Begin the timeout."""
        self.thread.start()

    def _wait(self):
        with self.cond:
            self.cond.wait(self.seconds)

            if not self.cancelled:
                self.timed_out()

    def cancel(self):
        """Cancel the timeout, if it hasn't yet occured."""
        with self.cond:
            self.cancelled = True
            self.cond.notify()
        self.thread.join()

    def timed_out(self):
        """The timeout has expired."""
        raise NotImplementedError

class KillProcessThread(TimeoutThread):
    def __init__(self, seconds, pid):
        super(KillProcessThread, self).__init__(seconds)
        self.pid = pid

    def timed_out(self):
        try:
            os.kill(self.pid, signal.SIGKILL) // this is for linux you need to change it for windows
        except OSError,e:
            # If the process is already gone, ignore the error.
            if e.errno not in (errno.EPERM, errno. ESRCH):
                raise e

@contextmanager
def processTimeout(seconds, pid):
    timeout = KillProcessThread(seconds, pid)
    timeout.run()
    try:
        yield
    finally:
        timeout.cancel()


def example(cmd):
    proc = subprocess.Popen(cmd, stderr=subprocess.PIPE, stdout=subprocess.PIPE)
    //setting the timeout to be 1 sec
    with processTimeout(1, proc.pid):
        stdout,stderr=proc.communicate()       

    resultcode = proc.wait()
    if resultcode < 0:
        #print "error: %i" % resultcode
        return resultcode,0
    else:
        return stdout,stderr





//This is used to create new subprocess and it will return output as well as error
output,err=example(["python",filepath,"5"])