Py_DecodeLocale() incorrect signature

[indygreg]

Currently Py_DecodeLocale() is defined as the following:

pub fn Py_DecodeLocale(arg1: *const c_char, arg2: Py_ssize_t) -> *mut wchar_t;

But in CPython Include/fileutils.h, it is defined as the following:

PyAPI_FUNC(wchar_t *) Py_DecodeLocale(
    const char *arg,
    size_t *size);

I believe the Rust signature should be:

pub fn Py_DecodeLocale(arg1: *const c_char, arg2: *mut Py_ssize_t) -> *mut wchar_t;

Given this is an API change, I'm unsure how you want to handle this. Hence why I filed an issue instead of going straight to a PR.

[davidhewitt]

Yep looks like our ffi definition is wrong; the C declaration you quote has been the same since Python 3.6 (and maybe earlier, didn't check).

Given our declaration is wrong I class this as a bug fix that's fine to be merged whenever. It seems unlikely anyone is using this correctly at the moment.