Fatal LookupError: unknown encoding: cp0 on Windows embedded startup.

Modules/posixmodule.c

 
 /* POSIX module implementation */
 
 /* This file is also used for Windows NT/MS-Win and OS/2.  In that case the
    module actually calls itself 'nt' or 'os2', not 'posix', and a few
    functions are either unimplemented or implemented differently.  The source
    assumes that for Windows NT, the macro 'MS_WINDOWS' is defined independent
    of the compiler used.  Different compilers define their own feature
    test macro, e.g. '__BORLANDC__' or '_MSC_VER'.  For OS/2, the compiler
    independent macro PYOS_OS2 should be defined.  On OS/2 the default
@@ skipping 8477 matching lines @@
 
 PyDoc_STRVAR(device_encoding__doc__,
 "device_encoding(fd) -> str\n\n\
 Return a string describing the encoding of the device\n\
 if the output is a terminal; else return None.");
 
 static PyObject *
 device_encoding(PyObject *self, PyObject *args)
 {
     int fd;
+#if defined(MS_WINDOWS) || defined(MS_WIN64)
+    UINT cp;
+#endif
     if (!PyArg_ParseTuple(args, "i:device_encoding", &fd))
         return NULL;
     if (!_PyVerify_fd(fd) || !isatty(fd)) {
         Py_INCREF(Py_None);
         return Py_None;
     }
 #if defined(MS_WINDOWS) || defined(MS_WIN64)
-    if (fd == 0) {
-        char buf[100];
-        sprintf(buf, "cp%d", GetConsoleCP());
-        return PyUnicode_FromString(buf);
-    }
-    if (fd == 1 || fd == 2) {
-        char buf[100];
-        sprintf(buf, "cp%d", GetConsoleOutputCP());
-        return PyUnicode_FromString(buf);
-    }
+    if (fd == 0)
+        cp = GetConsoleCP();
+    else if (fd == 1 || fd == 2)
+        cp = GetConsoleOutputCP();
+    else
+        cp = 0;
+    /* GetConsoleCP() and GetConsoleOutputCP() return 0 if the application
+       has no console */
+    if (cp != 0)
+        return PyUnicode_FromFormat("cp%u", (unsigned int)cp);
 #elif defined(CODESET)
     {
         char *codeset = nl_langinfo(CODESET);
         if (codeset != NULL && codeset[0] != 0)
             return PyUnicode_FromString(codeset);
     }
 #endif
     Py_INCREF(Py_None);
     return Py_None;
 }
@@ skipping 1642 matching lines @@
 
 
 #endif /* __APPLE__ */
     return m;
 
 }
 
 #ifdef __cplusplus
 }
 #endif