+ By default, no validation is done on form fields. You can associate a
+ form with with a <I>field</I> <I>type</I>, making the form library validate input.
+
+
+</PRE><H3><a name="h3-field_arg">field_arg</a></H3><PRE>
+ Returns a pointer to the field's argument block. The <I>argument</I> <I>block</I> is
+ an opaque structure containing a copy of the arguments provided in a
+ <B>set_field_type</B> call.
+
+
+</PRE><H3><a name="h3-field_type">field_type</a></H3><PRE>
+ Returns a pointer to the <I>field</I> <I>type</I> associated with the form field,
+ i.e., by calling <B>set_field_type</B>.
+
+
+</PRE><H3><a name="h3-set_field_type">set_field_type</a></H3><PRE>
+ The function <B>set_field_type</B> associates a field type with a given form
+ field. This is the type checked by validation functions. Most field
+ types are configurable, via arguments which the caller provides when
+ calling <B>set_field_type</B>.
+
+ Several field types are predefined by the form library.
+
+
+</PRE><H3><a name="h3-Predefined-types">Predefined types</a></H3><PRE>
+ It is possible to set up new programmer-defined field types. Field
+ types are implemented via the <B>FIELDTYPE</B> data structure, which contains
+ several pointers to functions.
+
+ See the <B><A HREF="form_fieldtype.3X.html">form_fieldtype(3X)</A></B> manual page, which describes functions which
+ can be used to construct a field-type dynamically.
+
+ The predefined types are as follows: