[Python-Dev] builtin_id() returns negative numbers

James Y Knight foom at fuhm.net
Mon Feb 14 17:33:13 CET 2005

On Feb 14, 2005, at 10:41 AM, Tim Peters wrote:

>> Wouldn't it be more elegant to make builtin_id() return an unsigned
>> long integer?
> I think so.  This is the function ZODB 3.3 uses, BTW:
> def positive_id(obj):
>     """Return id(obj) as a non-negative integer."""
>  [...]

I think it'd be nice to change it, too. Twisted also uses a similar 

However, last time this topic came up, this Tim Peters guy argued 
against it. ;)


> Python doesn't promise to return a postive integer for id(), although
> it may have been nicer if it did.  It's dangerous to change that now,
> because some code does depend on the "32 bit-ness as a signed integer"
> accident of CPython's id() implementation on 32-bit machines.  For
> example, code using struct.pack(), or code using one of ZODB's
> specialized int-key BTree types with id's as keys.


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