[New-bugs-announce] [issue29392] msvcrt.locking crashes python

[Frazer McLean]

New submission from Frazer McLean:

On 3.5.2 and 3.5.3, but not 3.4.3 or 2.7.10 (Windows 64-bit), the third line causes Python to crash with exit code 0xC0000417.

import msvcrt
fp = open('file.txt', 'w')
msvcrt.locking(fp.fileno(), msvcrt.LK_NBLCK, -1)
print('End')

I came across this in the portalocker module. I don't think -1 is a valid third argument, but it doesn't raise an exception on Python 3.4 or 2.7.

----------
components: Windows
messages: 286495
nosy: RazerM, paul.moore, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
status: open
title: msvcrt.locking crashes python
type: crash
versions: Python 3.5

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue29392>
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