diff --git a/ap/libc/glibc/glibc-2.23/stdio-common/cuserid.c b/ap/libc/glibc/glibc-2.23/stdio-common/cuserid.c
new file mode 100644
index 0000000..574b464
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/stdio-common/cuserid.c
@@ -0,0 +1,32 @@
+/* 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 <stdio.h>
+#include <errno.h>
+
+/* Return the username of the caller.
+   If S is not NULL, it points to a buffer of at least L_cuserid bytes
+   into which the name is copied; otherwise, a static buffer is used.  */
+char *
+cuserid (char *s)
+{
+  __set_errno (ENOSYS);
+  return NULL;
+}
+
+
+stub_warning (cuserid)