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"""This test checks for correct fork() behavior.
We want fork1() semantics -- only the forking thread survives in the
child after a fork().
On some systems (e.g. Solaris without posix threads) we find that all
active threads survive in the child after a fork(); this is an error.
On BeOS, you CANNOT mix threads and fork(), the behaviour is undefined.
That's OK, fork() is a grotesque hack anyway. ;-) [cjh]
"""
import os, sys, time, thread
from test_support import verify, verbose, TestSkipped
try:
if os.uname()[0] == "BeOS":
raise TestSkipped, "can't mix os.fork with threads on BeOS"
except AttributeError:
pass
try:
os.fork
except AttributeError:
raise TestSkipped, "os.fork not defined -- skipping test_fork1"
LONGSLEEP = 2
SHORTSLEEP = 0.5
NUM_THREADS = 4
alive = {}
stop = 0
def f(id):
while not stop:
alive[id] = os.getpid()
try:
time.sleep(SHORTSLEEP)
except IOError:
pass
def main():
for i in range(NUM_THREADS):
thread.start_new(f, (i,))
time.sleep(LONGSLEEP)
a = alive.keys()
a.sort()
verify(a == range(NUM_THREADS))
prefork_lives = alive.copy()
cpid = os.fork()
if cpid == 0:
# Child
time.sleep(LONGSLEEP)
n = 0
for key in alive.keys():
if alive[key] != prefork_lives[key]:
n = n+1
os._exit(n)
else:
# Parent
spid, status = os.waitpid(cpid, 0)
verify(spid == cpid)
verify(status == 0,
"cause = %d, exit = %d" % (status&0xff, status>>8) )
global stop
# Tell threads to die
stop = 1
time.sleep(2*SHORTSLEEP) # Wait for threads to die
main()
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