Issue 8781: On systems a signed 4-byte wchar_t and a 4-byte Py_UNICODE, use memcpy to convert between the two (as already done when wchar_t is unsigned)

Modules/_ctypes/callproc.c

@@ -658,7 +658,7 @@ static int ConvParam(PyObject *obj, Py_ssize_t index, struct argument *pa)
 
 #ifdef CTYPES_UNICODE
     if (PyUnicode_Check(obj)) {
-#ifdef HAVE_USABLE_WCHAR_T
+#if Py_UNICODE_SIZE == SIZEOF_WCHAR_T
         pa->ffi_type = &ffi_type_pointer;
         pa->value.p = PyUnicode_AS_UNICODE(obj);
         Py_INCREF(obj);

Modules/_ctypes/cfield.c

@@ -1420,12 +1420,11 @@ Z_set(void *ptr, PyObject *value, Py_ssize_t size)
         return NULL;
     } else
         Py_INCREF(value);
-#ifdef HAVE_USABLE_WCHAR_T
-    /* HAVE_USABLE_WCHAR_T means that Py_UNICODE and wchar_t is the same
-       type.  So we can copy directly.  Hm, are unicode objects always NUL
+#if Py_UNICODE_SIZE == SIZEOF_WCHAR_T
+    /* We can copy directly.  Hm, are unicode objects always NUL
        terminated in Python, internally?
      */
-    *(wchar_t **)ptr = PyUnicode_AS_UNICODE(value);
+    *(wchar_t **)ptr = (wchar_t *) PyUnicode_AS_UNICODE(value);
     return value;
 #else
     {

Modules/_localemodule.c

@@ -289,15 +289,15 @@ PyLocale_strxfrm(PyObject* self, PyObject* args)
     wchar_t *s, *buf = NULL;
     size_t n1, n2;
     PyObject *result = NULL;
-#ifndef HAVE_USABLE_WCHAR_T
+#if Py_UNICODE_SIZE != SIZEOF_WCHAR_T
     Py_ssize_t i;
 #endif
 
     if (!PyArg_ParseTuple(args, "u#:strxfrm", &s0, &n0))
         return NULL;
 
-#ifdef HAVE_USABLE_WCHAR_T
-    s = s0;
+#if Py_UNICODE_SIZE == SIZEOF_WCHAR_T
+    s = (wchar_t *) s0;
 #else
     s = PyMem_Malloc((n0+1)*sizeof(wchar_t));
     if (!s)
@@ -326,7 +326,7 @@ PyLocale_strxfrm(PyObject* self, PyObject* args)
     result = PyUnicode_FromWideChar(buf, n2);
  exit:
     if (buf) PyMem_Free(buf);
-#ifndef HAVE_USABLE_WCHAR_T
+#if Py_UNICODE_SIZE != SIZEOF_WCHAR_T
     PyMem_Free(s);
 #endif
     return result;

Objects/unicodeobject.c

@@ -664,7 +664,7 @@ PyObject *PyUnicode_FromWideChar(register const wchar_t *w,
         return NULL;
 
     /* Copy the wchar_t data into the new object */
-#ifdef HAVE_USABLE_WCHAR_T
+#if Py_UNICODE_SIZE == SIZEOF_WCHAR_T
     memcpy(unicode->str, w, size * sizeof(wchar_t));
 #else
     {
@@ -1167,7 +1167,7 @@ Py_ssize_t PyUnicode_AsWideChar(PyUnicodeObject *unicode,
     if (size > PyUnicode_GET_SIZE(unicode))
         size = PyUnicode_GET_SIZE(unicode) + 1;
 
-#ifdef HAVE_USABLE_WCHAR_T
+#if Py_UNICODE_SIZE == SIZEOF_WCHAR_T
     memcpy(w, unicode->str, size * sizeof(wchar_t));
 #else
     {