[Tutor] Buffering problem using subprocess module
Smith, Jeff
jsmith at medplus.com
Tue Jul 19 14:34:25 CEST 2005
I am using the subprocess module in 2.4. Here's the fragment:
bufcaller.py:
import sys, subprocess
proc = subprocess.Popen('python bufcallee.py', bufsize=0,
shell=True, stdout=subprocess.PIPE)
for line in proc.stdout:
sys.stdout.write(line)
bufcallee.py:
import time
print 'START'
time.sleep(10)
print 'STOP'
Although the documentation says that the output should be unbuffered
(bufsize=0) the program (bufcaller) pauses for 10 seconds and then
prints START immediately followed by 'STOP' rather than pausing 10
seconds in between them. Note that I made bufcallee a Python script for
ease of the example but in the real-world problem I am trying to solve
it is simply an executable.
Any ideas?
Jeff
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