import os
import sys
import errno
import select
from signal import signal, SIGCHLD
from optparse import OptionParser
from functools import partial

def main(argv):
    options, args = parse_args(sys.argv[1:])
    if options.set_handler:
        signal(options.signal_number, handler)
    if options.until_concludes:
        _select = lambda *a: until_concludes(select.select, *a)
    else:
        _select = select.select
    print('%d blocking, kill() me' % (os.getpid(),))
    try:
        _select([], [], [])
        print('select returned')
    except KeyboardInterrupt:
        print('Ctrl-C caught')

def until_concludes(f, *a, **kw):
    while True:
        try:
            return f(*a, **kw)
        except (IOError, OSError, select.error) as e:
            if e.args[0] == errno.EINTR:
                continue
            raise

def handler(sig, frame):
    print('%d interrups at %s' % (sig, frame,))

def parse_args(args):
    parser = OptionParser()
    parser.add_option("--until-concludes", action="store_true", default=False)
    parser.add_option("--set-handler", action="store_true", default=False)
    parser.add_option("--signal-number", type="int", default=SIGCHLD)
    return parser.parse_args(args=args)

if __name__ == '__main__':
    main(sys.argv)