diff --git a/form/fty_alnum.c b/form/fty_alnum.c
new file mode 100644
index 0000000..59dd273
--- /dev/null
+++ b/form/fty_alnum.c
@@ -0,0 +1,167 @@
+/****************************************************************************
+ * Copyright (c) 1998-2006,2007 Free Software Foundation, Inc.              *
+ *                                                                          *
+ * Permission is hereby granted, free of charge, to any person obtaining a  *
+ * copy of this software and associated documentation files (the            *
+ * "Software"), to deal in the Software without restriction, including      *
+ * without limitation the rights to use, copy, modify, merge, publish,      *
+ * distribute, distribute with modifications, sublicense, and/or sell       *
+ * copies of the Software, and to permit persons to whom the Software is    *
+ * furnished to do so, subject to the following conditions:                 *
+ *                                                                          *
+ * The above copyright notice and this permission notice shall be included  *
+ * in all copies or substantial portions of the Software.                   *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
+ * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
+ * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
+ *                                                                          *
+ * Except as contained in this notice, the name(s) of the above copyright   *
+ * holders shall not be used in advertising or otherwise to promote the     *
+ * sale, use or other dealings in this Software without prior written       *
+ * authorization.                                                           *
+ ****************************************************************************/
+
+/***************************************************************************
+*                                                                          *
+*  Author : Juergen Pfeifer                                                *
+*                                                                          *
+***************************************************************************/
+
+#include "form.priv.h"
+
+MODULE_ID("$Id: fty_alnum.c,v 1.21 2007/10/13 19:31:52 tom Exp $")
+
+#define thisARG alnumARG
+
+typedef struct
+  {
+    int width;
+  }
+thisARG;
+
+/*---------------------------------------------------------------------------
+|   Facility      :  libnform
+|   Function      :  static void *Make_This_Type(va_list *ap)
+|
+|   Description   :  Allocate structure for alphanumeric type argument.
+|
+|   Return Values :  Pointer to argument structure or NULL on error
++--------------------------------------------------------------------------*/
+static void *
+Make_This_Type(va_list *ap)
+{
+  thisARG *argp = typeMalloc(thisARG, 1);
+
+  if (argp)
+    {
+      T((T_CREATE("thisARG %p"), argp));
+      argp->width = va_arg(*ap, int);
+    }
+
+  return ((void *)argp);
+}
+
+/*---------------------------------------------------------------------------
+|   Facility      :  libnform
+|   Function      :  static void *Copy_ThisType(const void *argp)
+|
+|   Description   :  Copy structure for alphanumeric type argument.
+|
+|   Return Values :  Pointer to argument structure or NULL on error.
++--------------------------------------------------------------------------*/
+static void *
+Copy_This_Type(const void *argp)
+{
+  const thisARG *ap = (const thisARG *)argp;
+  thisARG *result = typeMalloc(thisARG, 1);
+
+  if (result)
+    {
+      T((T_CREATE("thisARG %p"), result));
+      *result = *ap;
+    }
+
+  return ((void *)result);
+}
+
+/*---------------------------------------------------------------------------
+|   Facility      :  libnform
+|   Function      :  static void Free_This_Type(void *argp)
+|
+|   Description   :  Free structure for alphanumeric type argument.
+|
+|   Return Values :  -
++--------------------------------------------------------------------------*/
+static void
+Free_This_Type(void *argp)
+{
+  if (argp)
+    free(argp);
+}
+
+/*---------------------------------------------------------------------------
+|   Facility      :  libnform
+|   Function      :  static bool Check_This_Character(
+|                                      int c,
+|                                      const void *argp)
+|
+|   Description   :  Check a character for the alphanumeric type.
+|
+|   Return Values :  TRUE  - character is valid
+|                    FALSE - character is invalid
++--------------------------------------------------------------------------*/
+static bool
+Check_This_Character(int c, const void *argp GCC_UNUSED)
+{
+#if USE_WIDEC_SUPPORT
+  if (iswalnum((wint_t) c))
+    return TRUE;
+#endif
+  return (isalnum(UChar(c)) ? TRUE : FALSE);
+}
+
+/*---------------------------------------------------------------------------
+|   Facility      :  libnform
+|   Function      :  static bool Check_This_Field(
+|                                      FIELD *field,
+|                                      const void *argp)
+|
+|   Description   :  Validate buffer content to be a valid alphanumeric value
+|
+|   Return Values :  TRUE  - field is valid
+|                    FALSE - field is invalid
++--------------------------------------------------------------------------*/
+static bool
+Check_This_Field(FIELD *field, const void *argp)
+{
+  int width = ((const thisARG *)argp)->width;
+  unsigned char *bp = (unsigned char *)field_buffer(field, 0);
+  bool result = (width < 0);
+
+  Check_CTYPE_Field(result, bp, width, Check_This_Character);
+  return (result);
+}
+
+static FIELDTYPE typeTHIS =
+{
+  _HAS_ARGS | _RESIDENT,
+  1,				/* this is mutable, so we can't be const */
+  (FIELDTYPE *)0,
+  (FIELDTYPE *)0,
+  Make_This_Type,
+  Copy_This_Type,
+  Free_This_Type,
+  Check_This_Field,
+  Check_This_Character,
+  NULL,
+  NULL
+};
+
+NCURSES_EXPORT_VAR(FIELDTYPE*) TYPE_ALNUM = &typeTHIS;
+
+/* fty_alnum.c ends here */