Random "pythonw.exe has stopped working" crashing

Question

SO, The code in question is the following, however it can randomly happen on other scripts too (I don't think the error lies in the code) For some reason, completely randomly it sometimes crashes and pops up that "pythonw.exe has stopped working" it could be after 5 hours, 24 hours or 5 days... I can't figure out why it's crashing. ``` from datetime import date, timedelta from sched import scheduler from time import time, sleep, strftime import random import traceback s = scheduler(time, sleep) random.seed() def periodically(runtime, intsmall, intlarge, function): currenttime = strftime('%H:%M:%S') with open('eod.txt') as o: eod = o.read().strip() if eod == "1": EOD_T = True else: EOD_T = False while currenttime >= '23:40:00' and currenttime <= '23:59:59' or currenttime >= '00:00:00' and currenttime <= '11:30:00' or EOD_T: if currenttime >= '23:50:00' and currenttime <= '23:59:59': EOD_T = False currenttime = strftime('%H:%M:%S') print currenttime, "Idling..." sleep(10) open("tca.txt"…

Accepted Answer

I don't know, but it may be related to the two lines that do this:

```
open("tca.txt", 'w').close
```

Those aren't doing what you intend them to do: they leave the file open. You need to call the close method (not merely retrieve it):

```
open("tca.txt", 'w').close()
                          ^^
```

But that's probably not it. CPython will automatically close the file object when it becomes garbage (which happens immediately in this case - refcount hits 0 as soon as the statement ends).

Maybe you should move to a Linux system ;-)

Idea: would it be possible to run this with `python.exe` instead, from a DOS box (`cmd.exe`) you leave open and ignore? A huge problem with debugging `pythonw.exe` deaths is that there's no console window to show any error messages that may pop up.

Which leads to another question: what's this line doing?

```
print "Running..."
```

If you're running under `pythonw.exe`, you never see it, right? And that can cause problems, depending on exactly which versions of Python and Windows you're running. `Standard input` and `standard output` don't really exist, under `pythonw`, and I remember tracking down one mysterious `pythonw.exe` death to the Microsoft libraries blowing up when "too much" data was written to `sys.stdout` (which `print` uses).

One way to tell: if you run this under `python.exe` instead from a DOS box, and it runs for a year without crashing, that was probably the cause ;-)

Example

Here's a trivial program:

```
i = 0
while 1:
    i += 1
    with open("count.txt", "w") as f:
        print >> f, i
    print "hi!"
```

Using Python 2.7.6 under 32-bit Windows Vista, it has radically different behavior depending on whether `python.exe` or `pythonw.exe` is used to run it.

Under `python.exe`:

```
C:\Python27>python yyy.py
hi!
hi!
hi!
hi!
hi!
hi!
hi!
hi!
hi!
hi!
hi!
...
```

That goes on forever, and the value in `count.txt` keeps increasing. But:

```
C:\Python27>pythonw yyy.py

C:\Python27>
```

That is, there's no visible output. And that's expected: `pythonw` runs its program disconnected from the console window.

After a very short time, `pythonw.exe` silently dies (use Task Manager to see this) - vanishes without a trace. At that point:

```
C:\Python27>type count.txt
1025
```

So MS's libraries are still crapping out when "too much" is written to stdout from a disconnected program. Take out the `print "hi!"`, and it runs "forever".

Python 3

This is "fixed" in Python 3, via the dubious expedient of binding `sys.stdout` to `None` under its `pythonw.exe`. You can read the history of this mess here.

Random "pythonw.exe has stopped working" crashing

Solution

Problem