>>> sys.version
'2.3.3 (#51, Dec 18 2003, 20:22:39) [MSC v.1200 32 bit
(Intel)]'
>>> sys.platform
'win32'
>>> sys.getwindowsversion()
(5, 1, 2600, 2, '')


Hi.
I have written this script for reproducing the bug:



import sys

class teeIO:
    def __init__(self, *files):
        self.__files = files

    def write(self, str):
        for i in self.__files:
            print >> trace, 'writing on %s: %s' % (i, str)
            i.write(str)

        print >> trace, '-' * 70



def tee(*files):
    return teeIO(*files)


log = file('log.txt', 'w')
err = file('err.txt', 'w')
trace = file('trace.txt', 'w')

sys.stdout = tee(log, sys.__stdout__)
sys.stderr = tee(err, sys.__stderr__)

def write(n, width):
    sys.stdout.write('x' * width)
    if n == 1: return

    write(n - 1, width)
    
try:
    1/0
except:
    write(1, 4096)



[output from err.log]
Traceback (most recent call last):
  File "sys.py", line 36, in ?
    write(1, 4096)
  File "sys.py", line 28, in write
    sys.stdout.write('x' * width)
  File "sys.py", line 10, in write
    i.write(str)
IOError: [Errno 9] Bad file descriptor




TeeIO is needed for actually read the program output,
but I don't know if the problem is due to teeIO.

The same problem is present for stderr, as can be seen
by swapping sys.__stdout__ and sys.__stderr__.

As I can see, 4096 is the buffer size for sys.stdout/err.
The problem is the same if the data is written in
chunks, ad example: write(2, 4096/2).

The bug isn't present if I use python.exe or if I write
less than 4096 bytes.


Thanks and regards   Manlio Perillo