+#if _LIBC
+ if (_IO_fwide (stderr, 0) > 0)
+ {
+# define ALLOCA_LIMIT 2000
+ size_t len = strlen (message) + 1;
+ const wchar_t *wmessage = L"out of memory";
+ wchar_t *wbuf = (len < ALLOCA_LIMIT
+ ? alloca (len * sizeof *wbuf)
+ : len <= SIZE_MAX / sizeof *wbuf
+ ? malloc (len * sizeof *wbuf)
+ : NULL);
+
+ if (wbuf)
+ {
+ size_t res;
+ mbstate_t st;
+ const char *tmp = message;
+ memset (&st, '\0', sizeof (st));
+ res = mbsrtowcs (wbuf, &tmp, len, &st);
+ wmessage = res == (size_t) -1 ? L"???" : wbuf;
+ }
+
+ __vfwprintf (stderr, wmessage, args);
+ if (! (len < ALLOCA_LIMIT))
+ free (wbuf);
+ }
+ else
+#endif
+ vfprintf (stderr, message, args);
+ va_end (args);