Hello,
I have some function that output too much stuff to stderr when called,
and I have no control over the function itself. So I thought as a
workaround, I redirect stderr to /dev/null before calling that
function, and then revert the stderr back after calling that
function.
I have something like this:
def nullStderr():
sys.stderr.flus h()
err = open('/dev/null', 'a+', 0)
os.dup2(err.fil eno(), sys.stderr.file no())
def revertStderr():
sys.stderr = sys.__stderr__
Then when calling the function, I want to do:
nullStderr()
noisyFunction(f oo, bar)
revertStderr()
The problem is the "revertStderr() " doesn't work, ie. I still get no
stderr back after calling it (stderr still redirects to /dev/null). I
want stderr back so that when the script fails in different places
later I can get error messages. What am I missing here ? Thanks a lot
for any help.
RDB 1 3079
reubendb wrote:
def nullStderr():
sys.stderr.flus h()
err = open('/dev/null', 'a+', 0)
os.dup2(err.fil eno(), sys.stderr.file no())
def revertStderr():
sys.stderr = sys.__stderr__
You're doing the redirection at one level and
trying to revert it at a different level.
If this is a Python function that's doing its
output by writing to sys.stderr, there's a
much simpler way to do the redirection:
sys.stderr = open('/dev/null', 'w')
(that's the Python builtin function 'open',
not the one in os). Then your revertStderr
function will work.
BTW I'd arrange for the reversion to be done
in a try-finally, e.g.
nullStderr()
try:
do_something()
finally:
revertStderr()
so you won't get stuck with a redirected stderr
if an exception occurs, and thereby not be able
to see the traceback!
--
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