Hello everyone,
I have started using multiprocessing module, which is now available
with Python 2.6.
It definitely opens up new possibilities.
Now, I developed a small GUI package, which is to be used from other
programs.
It uses multiprocessing and Pipes are used to pump image data/command
to the GUI process.
(I used multiprocessing because I got stack size problem if I used
threading)
It works great under Solaris environment, which is my primary
development environment.
When I tried the program under Linux (CentOS5), the program didn't
work (it hung).
My other programs that use multiprocessing work flawlessly under both
Solaris and Linux.
To investigate this problem, I create a much simpler test program. The
test program uses only basic necessary codes, nothing else. But my
simple test program still exhibits the same problem.
My test program display a GUI Button using three possible approaches:
(1) multiprocessing (Solaris - okay, Linux - hung)
(2) threading (Solaris - okay, Linux - okay)
(3) none (main thread) (Solaris - okay, Linux - okay)
Is this a bug in a multiprocessing package? Or, I overlooked
something?
Any comments on resolving this problem will be greatly appreciated.
The attached is my test program (sorry for posting a long program).
Thank you!
Aki Niimura
#!/usr/bin/env python
import sys, os
import time
import threading
import multiprocessing
from Tkinter import *
###
### class Panel
###
class Panel:
def __init__(self, subp='multip'):
if subp == 'multip':
print 'multiprocessing module to handle'
# GUI process
self.process1 = multiprocessing.Process(target=self.draw)
self.process1.start()
elif subp == 'thread':
print 'threading module to handle'
# GUI thread
self.thread1 = threading.Thread(target=self.draw)
self.thread1.start()
# self.thread1.setDaemon(1)
else:
print 'main thread to handle'
pass
def draw(self):
self.root = Tk()
w = Button(self.root, text='Exit', command=self.root.quit)
w.pack()
self.root.mainloop()
###
### Main routine
###
def main():
subp = 'multip'
if len(sys.argv) >= 2:
if not sys.argv[1] in ['multip', 'thread', 'none',]:
print 'Invalid option: %s' % sys.argv[1]
print "Valid options are 'multip', 'thread', 'none'"
sys.exit(1)
else:
subp = sys.argv[1]
panel = Panel(subp)
if subp == 'none':
panel.draw()
while 1:
time.sleep(1)
pass
if __name__ == '__main__':
main()
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