ctypes.WinError & OSError

[simonzack]

BPO	22961
Nosy	@amauryfa, @abalkin, @meadori, @eryksun

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-02-23.11:28:38.380>
created_at = <Date 2014-11-28.06:37:34.480>
labels = ['ctypes', 'invalid']
title = 'ctypes.WinError & OSError'
updated_at = <Date 2021-02-23.11:28:38.380>
user = 'https://bugs.python.org/simonzack'

bugs.python.org fields:

activity = <Date 2021-02-23.11:28:38.380>
actor = 'eryksun'
assignee = 'none'
closed = True
closed_date = <Date 2021-02-23.11:28:38.380>
closer = 'eryksun'
components = ['ctypes']
creation = <Date 2014-11-28.06:37:34.480>
creator = 'simonzack'
dependencies = []
files = []
hgrepos = []
issue_num = 22961
keywords = []
message_count = 4.0
messages = ['231796', '231805', '231806', '231823']
nosy_count = 5.0
nosy_names = ['amaury.forgeotdarc', 'belopolsky', 'meador.inge', 'eryksun', 'simonzack']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue22961'
versions = ['Python 3.4']

[simonzack]

The ctypes.WinError function returns:

    OSError(None, descr, None, code)

However OSError does not appear to allow None as a first argument, and converts it to 22 which is the EINVAL "Invalid Argument" error. This is rather confusing as there was no invalid argument errors in the code.

I think the behaviour for one of WinError and OSError should be modified so that the handling of errno is more compatible.

[amauryfa]

No, OSError.errno is converted from the Windows error code.

There is a translation map (see PC/errmap.h, built with the _dosmaperr() function) and the default value is EINVAL.

It's working as intended. What was the winerror code? do you think it should be mapped to another errno?

[simonzack]

Ok, my bad, I was creating my own OSErrors so I was just testing it out. I just found the default to be rather confusing as I thought None would not be mapped to anything.

[eryksun]

the default value is EINVAL.

Should that be specified in the docs? Currently it states that "[t]he errno attribute is then an approximate translation, in POSIX terms, of that native error code".

https://docs.python.org/3/library/exceptions.html#OSError