test_exit.py

"""
This file can be used to demonstrate that the exit status of the process
that is run by a os.exec*() call will be taken as the exit status of the
original process, as can be expected from the fact that os.exec() completely
replaces the original process.

Use it like this on bash:

    python test_exit.py die 2 ; echo $?
    python test_exit.py sub 2 ; echo $?
    python test_exit.py exe 2 ; echo $?

On Windows CMD, you need to `echo %errorcode%` instead.

Replace "2" with whatever exit status you want to test.
"""

import sys
import os
import subprocess


def sub(status):
    args = [sys.executable, sys.argv[0], "die", status]
    print "running: sys.exit(subprocess.call({})".format(args)
    sys.exit(subprocess.call(args))


def exe(status):
    args = [sys.executable, sys.argv[0], sys.argv[0], "die", status]
    print "running: execl(*{})".format(args)
    sys.stdout.flush(); sys.stderr.flush()
    os.execl(*args)


def die(status):
    print "dying with status:", status
    sys.exit(int(status))

if __name__ == "__main__":
    globals()[sys.argv[1]](sys.argv[2])