[Python-Dev] Const-correctness in C-API Object Protocol

[Stefan Behnel]

Reid Kleckner, 22.02.2011 21:21:
> On Tue, Feb 22, 2011 at 2:09 PM, Eric Smith wrote:
>> Also changing it now would be a giant hassle, leading to so-called "const
>> poisoning" where many, many APIs need to be changed before everything would
>> again work.
>
> The poisoning will not break any users of the API, though, since they
> can pass const and non-const pointers.  Internally Python would have
> to go through and add const keywords as appropriate when passing
> strings around.  IMO it's worth it to not cause this warning for
> users.

The problem is that Python's C-API functions are used both internally and 
externally, so changes like this can easily impact other public API 
functions because the function being changed uses them. I think that's what 
"const poisoning" refers to here.

Stefan