import argparse
import os
import select
import sys


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('-c', '--kill-child', action='store_true')
    args = parser.parse_args()

    r, w = os.pipe()
    pid = os.fork()
    if args.kill_child:
        if not pid:
            # in child
            print 'child exiting'
            sys.exit(0)
        else:
            os.close(r)
            select.select([], [w], [])
            print 'parent saw child die'
    else:
        if not pid:
            os.close(w)
            # in child
            select.select([r], [], [])
            print 'child saw parent die'
        else:
            print 'parent exiting'
            sys.exit(0)


if __name__ == '__main__':
    main()