T_ULONG -> double rounding in PyMember_GetOne()

[pjdelport]

BPO	1566140
Nosy	@loewis

^{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 2006-10-27.06:19:48.000>
created_at = <Date 2006-09-27.05:23:51.000>
labels = ['interpreter-core']
title = 'T_ULONG -> double rounding in PyMember_GetOne()'
updated_at = <Date 2006-10-27.06:19:48.000>
user = 'https://bugs.python.org/pjdelport'

bugs.python.org fields:

activity = <Date 2006-10-27.06:19:48.000>
actor = 'loewis'
assignee = 'none'
closed = True
closed_date = None
closer = None
components = ['Interpreter Core']
creation = <Date 2006-09-27.05:23:51.000>
creator = 'pjdelport'
dependencies = []
files = []
hgrepos = []
issue_num = 1566140
keywords = []
message_count = 3.0
messages = ['30016', '30017', '30018']
nosy_count = 3.0
nosy_names = ['loewis', 'zseil', 'pjdelport']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1566140'
versions = ['Python 2.6']

[pjdelport]

Problem:

Python/structmember.c's PyMember_GetOne currently
handles getting T_ULONG members as follows:

case T_ULONG:
v = PyLong_FromDouble((double) *(unsigned
long*)addr);
break;

On platforms with 64-bit longs, the double won't have
enough precision to hold big values without rounding.

The fix should be simple:

v = PyLong_FromUnsignedLong(*(unsigned long*)addr);

-- Piet Delport <pjd@satori.za.net>

[zseil]

Logged In: YES
user_id=1326842

Patch bpo-1549049:
http://www.python.org/sf/1549049

has a fix for this and some other bugs.

[loewis]

Logged In: YES
user_id=21627

This was fixed with said patch.