Is there a safe way to run tkinter in a multithreaded app where the
mainloop runs in a background thread ?
Here's some test code demonstrating the problem. I'm running Python2.4
under Windows 2000.
----------------Code snip starts-------------
from Tkinter import *
def GetTkinterThread():
import threading
def TestTkinter():
def greeting():
print "Hello stdout world !"
win = Frame()
win.pack()
Label(win, text="Hello container world").pack(side=TOP)
Button(win, text="Hello", command=greeting).pack(side=TOP)
Button(win, text="Quit", command=win.quit).pack(side=RIGHT)
win.mainloop()
#Run the mainloop in another thread
t = threading.Thread(None, TestTkinter, 'Test Tkinter Thread')
t.setDaemon(1) #Keep going
t.start()
print 'Hi'
return t
t = GetTkinterThread() #This works fine
#Now press the "Hello" button on the Tkinter window
#Now press the return key at the python prompt
----------------Code snip ends-------------
With a debug build the call stack looks like this:
python24_d.dll!Py_FatalError(const char * msg=0x1e23ca14) Line
1513 C
python24_d.dll!PyThreadState_Swap(_ts * new=0x0098d0b8) Line
293 + 0xa C
python24_d.dll!PyEval_RestoreThread(_ts * tstate=0x0098d0b8)
Line 309 + 0x9 C
_tkinter_d.pyd!EventHook() Line 2969 + 0xc C
python24_d.dll!my_fgets(char * buf=0x009ef3e8, int len=100,
_iobuf * fp=0x1027c838) Line 46 C
python24_d.dll!PyOS_StdioReadline(_iobuf * sys_stdin=0x1027c838,
_iobuf * sys_stdout=0x1027c858, char * prompt=0x0087f974) Line 125 +
0x11 C
python24_d.dll!PyOS_Readline(_iobuf * sys_stdin=0x1027c838,
_iobuf * sys_stdout=0x1027c858, char * prompt=0x0087f974) Line 205 +
0x12 C
Is this because of access to sys.stdout ? Or some deeper darker problem
? Is there a right way to achieve this ? Basically I want to be able to
call a function from the Python prompt which creates a Tkinter window
(not necessarily interactive apart from a close button) to display some
data, but leaves the Python prompt active so I can carry on from there.
Haven't found anything about this yet. All sample multithreaded Tkinter
code I've seen uses the main thread as the GUI thread. Also, should I be
posting this to another newsgroup ?
Thanks for any help,
Mark
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