"Jane Austine" <ja***********@ hotmail.com> wrote in message
news:ba******** *************** ***@posting.goo gle.com...
Running Python 2.3 on Win XP
It seems like socket is working interdependentl y with subprocesses of
the process which created socket.
and the server side tries to close the socket:
...... Alas, the client side doesn't wake up! It doesn't wake up unless the
notepad is exited first; only after that, 'Connection reset by peer'
is raised. What does the socket has to do with subprocesses?
Hi Jane
I think it may be tied up with the way subprocesses are made under Windows.
Below is a copy of part of a post I made some months back when inexplicable
file-locking was causing me problems. It took me weeks to track down the
reason.
The Python default subprocess inherits open handles from the parent.
Your options are:
1. Open the subprocess before the socket.
2. Create the subprocess using win32 API primitives (this is what I had to
do).
Let me know if want details.
Colin Brown
PyNZ
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I have been struggling to solve why an occasional "Permission Denied" error
popped up from the following code fragment in one of my Win2K program
threads:
....
input_file = preprocess(raw_ file)
os.system('thir d_party input_file output_file > error_file')
if os.path.exists( saved_file):
os.remove(saved _file)
os.rename(input _file,saved_fil e)
....
The error occurs on the os.rename(). The third_party executable was closing
input_file before terminating and anyway the subshell process has finished
before the os.rename is called! Most baffling.
With the aid of handle.exe from
www.sysinternals.com I finally resolved the
problem. To see the problem at first hand try the following script:
import time, thread, os
def rm(file):
print 'delete x.x'
os.remove(file)
def wait():
if os.name == 'nt':
os.system('paus e')
elif os.name == 'posix':
os.system('slee p 3')
print 'end wait'
print 'create x.x'
f = open('x.x','w')
thread.start_ne w_thread(wait,( ))
time.sleep(1)
print '\nclose x.x'
f.close()
rm('x.x')
Although this works fine on Linux, I get a Permission Denied error on
Windows. I surmise that an os.system call uses a C fork to create the
subshell - an exact duplicate of the current process environment including
OPEN FILE HANDLES. Because the os.system call has not returned before the
os.remove is called a "Permission Denied" error occurs. Quite simple really.
Now going back to my original problem, I had other threads doing os.system
calls. When one of these calls happens during the preprocess file write of
my above thread AND takes longer to complete than the os.system call in the
above thread then the file will still be open and the os.rename will return
the Permission Denied error.
