Strangeness: Cannot write to a file from a process created by Windows Task Scheduler ...

[Sandy Walsh]

Hi there,

Seeing some really weird behavior and perhaps someone has seen something 
similar:


I have a python script that launches as a Windows Scheduled Task. The 
program simply opens a disk file and writes some text to it:


---
f = open(waiting.txt, w)
x = 0
while 1:
   f.write(Sleeping: %d\r\n % x)
   x += 1
   time.sleep(2)

f.close()
---

I've run it under my user account. I've run it as Local Account. I've 
run it via pythonw and python ... only one way works:


When I run with full credentials (not local account) and python (not 
pythonw) I get output in the file (and a CMD window appears while it's 
running). In every other combination it creates the 'waiting.txt' file, 
but doesn't write any output to the file. The length of the file is 0 bytes.


Anyone have ideas what could be causing this? I suspect it's blocking on 
something, but I can't imagine where.


There is no stderr/stdout output anywhere in the program so it's not 
blocking on anything stdio related (that I can imagine)


Thoughts?
-Sandy


attachment: swalsh.vcf-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Strangeness: Cannot write to a file from a process created by Windows Task Scheduler ...

[MRAB]

Sandy Walsh wrote:
Yes it seems to be a flush problem. Strange how it doesn't require the 
explicit flush() when the console window appears, but does otherwise. 
Either way, it gives me a good direction to chase after.



[snip]
It buffers for efficiency reasons, but if it can detect that it's
connected to a console then it won't bother buffering because there's
nothing to gain.

--
http://mail.python.org/mailman/listinfo/python-list