diff --git a/ap/libc/glibc/glibc-2.23/stdlib/mbstowcs.c b/ap/libc/glibc/glibc-2.23/stdlib/mbstowcs.c
new file mode 100644
index 0000000..735a309
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/stdlib/mbstowcs.c
@@ -0,0 +1,39 @@
+/* Copyright (C) 1991-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+
+/* Convert the string of multibyte characters in S to `wchar_t's in
+   PWCS, writing no more than N.  Return the number written,
+   or (size_t) -1 if an invalid multibyte character is encountered.
+
+   Attention: this function should NEVER be intentionally used.
+   The interface is completely stupid.  The state is shared between
+   all conversion functions.  You should use instead the restartable
+   version `mbsrtowcs'.  */
+size_t
+mbstowcs (wchar_t *pwcs, const char *s, size_t n)
+{
+  mbstate_t state;
+
+  memset (&state, '\0', sizeof state);
+  /* Return how many we wrote (or maybe an error).  */
+  return __mbsrtowcs (pwcs, &s, n, &state);
+}