ctypes.string_at(buf, 0) is seen as zero-terminated-string

[johannes]

BPO	1646630
Nosy	@theller

^{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 = 'https://github.com/theller'
closed_at = <Date 2007-03-09.20:23:22.000>
created_at = <Date 2007-01-28.22:18:20.000>
labels = ['extension-modules']
title = 'ctypes.string_at(buf, 0) is seen as zero-terminated-string'
updated_at = <Date 2007-03-09.20:23:22.000>
user = 'https://bugs.python.org/johannes'

bugs.python.org fields:

activity = <Date 2007-03-09.20:23:22.000>
actor = 'theller'
assignee = 'theller'
closed = True
closed_date = None
closer = None
components = ['Extension Modules']
creation = <Date 2007-01-28.22:18:20.000>
creator = 'johannes'
dependencies = []
files = []
hgrepos = []
issue_num = 1646630
keywords = []
message_count = 2.0
messages = ['31111', '31112']
nosy_count = 2.0
nosy_names = ['theller', 'johannes']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1646630'
versions = ['Python 2.5']

[johannes]

ctypes.string_at() interprets size=0 wrong.

When the size argument is 0, ctypes.string_at (and probably wstring_at too) string_at tries to read an zero-terminated string instead of an empty string.

Python 2.5 (r25:51908, Oct  6 2006, 15:22:41) 
[GCC 4.1.2 20060928 (prerelease) (Ubuntu 4.1.1-13ubuntu4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from ctypes import *
>>> bytes = (c_char*3)("1", "2", "\0")
>>> string_at(pointer(bytes))
'12'
>>> string_at(pointer(bytes), 0)
'12'
>>> string_at(pointer(bytes), 1)
'1'

instead of:

>>> string_at(pointer(bytes), 0)
''

[theller]

Fixed in rev. 54244 (trunk) and rev. 54246 (release25-maint).