On 2/4/2013 7:09 PM, Jabba Laci wrote:
Hi,
Thanks for the answers. I like the context manager idea but setting
the sys.stdout back to the original value doesn't work.
Example:
class Unbuff(object):
def __init__(self):
self.stdout_bak = sys.stdout
This could/should go in the __enter__ method. You do not need __init__ here.
def __enter__(self):
sys.stdout.flush()
sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)
This creates a new *python* object but perhaps it does something at the
OS level that does not get reversed.
def __exit__(self, exc_type, exc_val, exc_tb):
sys.stdout = self.stdout_bak
####
with Unbuff():
for i in range(5):
sys.stdout.write('.')
sleep(.5)
from the time module :-?
#
sys.stdout.write('EXIT') # provokes an error
The problem is in __exit__ when sys.stdout is pointed to the old
value. sys.stdout.write doesn't work from then on. Output:
.....close failed in file object destructor:
sys.excepthook is missing
lost sys.stderr
In 3.3, Win7, with the regular interpreter, I get
File "<stdin>", line 5, in __enter__
File "C:\Programs\Python33\lib\os.py", line 1032, in fdopen
return io.open(fd, *args, **kwargs)
ValueError: can't have unbuffered text I/O
If I change the mode to 'wb', I get
File "C:\Programs\Python33\lib\os.py", line 1032, in fdopen
return io.open(fd, *args, **kwargs)
OSError: [Errno 9] Bad file descriptor
With IDLE, I get
File "F:\Python\mypy\tem.py", line 7, in __enter__
sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)
AttributeError: fileno
It looks like you should perhaps just forget about reopening and just
use sys.stdout.flush(). This works fine even on IDLE.
import sys, time
for i in range(10):
sys.stdout.write('.'); sys.stdout.flush()
time.sleep(.5)
>>>
,,,,,,,,,,
Write a write_flush function if you want, and add any of the number,
string, and sleep time as parameters if you wish.
--
Terry Jan Reedy
--
http://mail.python.org/mailman/listinfo/python-list
