1"""This test checks for correct wait4() behavior.
2"""
3
4import os
5import time
6import sys
7from test.fork_wait import ForkWait
8from test.test_support import run_unittest, reap_children, get_attribute
9
10# If either of these do not exist, skip this test.
11get_attribute(os, 'fork')
12get_attribute(os, 'wait4')
13
14
15class Wait4Test(ForkWait):
16    def wait_impl(self, cpid):
17        option = os.WNOHANG
18        if sys.platform.startswith('aix'):
19            # Issue #11185: wait4 is broken on AIX and will always return 0
20            # with WNOHANG.
21            option = 0
22        for i in range(10):
23            # wait4() shouldn't hang, but some of the buildbots seem to hang
24            # in the forking tests.  This is an attempt to fix the problem.
25            spid, status, rusage = os.wait4(cpid, option)
26            if spid == cpid:
27                break
28            time.sleep(1.0)
29        self.assertEqual(spid, cpid)
30        self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
31        self.assertTrue(rusage)
32
33def test_main():
34    run_unittest(Wait4Test)
35    reap_children()
36
37if __name__ == "__main__":
38    test_main()
39