asm198 at gmail
Jul 3, 2009, 6:14 PM
Views: 233
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Problems with using queue in Tkinter application
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I'm working on a serial protocol analyzer in python. We have an
application written by someone else in MFC but we need something that
is cross platform. I intended to implement the GUI portion in Tkinter
but am having trouble.
The idea is that I will read messages from the serial port and output
them to a Tkinter Text object initially. Eventually it will have
other functionality but that's it for the short term. I've written
this little test app to experiment with putting things on the GUI via
a Queue which is polled by the Tkinter loop.
On some machines this code works fine and I get whatever I type in
displayed in the Text widget. On others I get errors like this as
soon as I start it running.
error in background error handler:
out of stack space (infinite loop?)
while executing
"::tcl::Bgerror {out of stack space (infinite loop?)} {-code 1 -level
0 -errorcode NONE -errorinfo {out of stack space (infinite loop?)
while execu..."
I don't understand why on some machines it works exactly as expected
and on others it acts the same way Tkinter does when I call functions
directly from outside the Tkinter thread. Does anyone have any
suggestions? The full code as appended below. Thanks in advance.
[code]
import Queue
class functionQueue:
def __init__(self, root = None, timeout = 250):
self.functionQueue = Queue.Queue()
self.root = root
self.timeout = timeout
if(self.root):
self.pop_function(root)
def pop_function(self, root = None):
try:
funcArgList = self.functionQueue.get(block = False)
except Queue.Empty:
pass
else:
try:
funcArgList[0](*funcArgList[1])
except:
try:
print "Failed to call function", funcArgList[0]
except:
print "Failed to call function"
if(root):
root.after(self.timeout, lambda: self.pop_function
(self.root))
def add_function(self, function, argList):
try:
self.functionQueue.put([function, argList])
except:
pass
if( __name__ == '__main__'):
import Tkinter
import thread
text = Tkinter.Text()
text.pack()
myQueue = functionQueue(text, 50)
def gui_loop():
try:
text.mainloop()
except:
import os
os._exit(1)
thread.start_new_thread(text.mainloop, ())
while(True):
usrInput = raw_input()
if(usrInput == "-1"):
import os
os._exit(0)
myQueue.add_function(text.insert, ['end', usrInput + "\n"])
myQueue.add_function(text.see, ['end'])
[/code]
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Problems with using queue in Tkinter application
