[Python-Dev] New Py_UNICODE doc

["Martin v. Löwis"]

Nicholas Bastin wrote:
>> Again, patches are welcome. I was opposed to Nick's proposed changes,
>> since they explicitly said that you are not supposed to know what
>> is in a Py_UNICODE. Integrating the essence of PEP 261 into the
>> main documentation would be a worthwhile task.
> 
> 
> You can't possibly assume you know specifically what's in a Py_UNICODE
> in any given python installation.  If someone thinks this statement is
> untrue, please explain why.

This is a different issue. Between saying "we don't know what
installation xyz uses" and saying "we cannot say anything" is a wide
range of things that you can truthfully say. Like "it can be either
two bytes or four bytes" (but not one or three bytes), and so on.

Also, for a given installation, you can find out by looking at
sys.maxunicode from Python, or at Py_UNICODE_SIZE from C.

> I realize you might not *want* that to be true, but it is.  Users are
> free to configure their python however they desire, and if that means
> --enable-unicode=ucs2 on RH9, then that is perfectly valid.

Sure they can. Of course, that will mean they don't get a working
_tkinter, unless they rebuild Tcl as well. Nevertheless, it is indeed
likely that people do that. So if you want to support them, you
need to distribute two versions of your binary module, or give
them source code.

Regards,
Martin