SYNOPSIS

       #include <form.h>
       int set_field_type(FIELD *field, FIELDTYPE *type, ...);
       FIELDTYPE *field_type(const FIELD *field);
       void *field_arg(const FIELD *field);

       FIELDTYPE *TYPE_ALNUM;
       FIELDTYPE *TYPE_ALPHA;
       FIELDTYPE *TYPE_ENUM;
       FIELDTYPE *TYPE_INTEGER;
       FIELDTYPE *TYPE_NUMERIC;
       FIELDTYPE *TYPE_REGEXP;
       FIELDTYPE *TYPE_IPV4;

DESCRIPTION

       The  function  set_field_type  declares  a  data  type for a given form
       field.  This is the type checked by validation functions.   The  prede-
       fined types are as follows:

       TYPE_ALNUM
            Alphanumeric data.  Requires a third int argument, a minimum field
            width.

       TYPE_ALPHA
            Character data.  Requires a third int argument,  a  minimum  field
            width.

       TYPE_ENUM
            Accept  one of a specified set of strings.  Requires a third (char
            **) argument pointing to a string list; a fourth int flag argument
            to enable case-sensitivity; and a fifth int flag argument specify-
            ing whether a partial match must be a unique one (if this flag  is
            off,  a  prefix matches the first of any set of more than one list
            elements with that prefix). Please notice that the string list  is
            not  copied, only a reference to it is stored in the field. So you
            should avoid using a list that lives in automatic variables on the
            stack.

       TYPE_INTEGER
            Integer data, parsable to an integer by atoi(3).  Requires a third
            int argument controlling the precision,  a  fourth  long  argument
            constraining  minimum value, and a fifth long constraining maximum
            value.  If the maximum value is less than or equal to the  minimum
            value,  the range is simply ignored. On return the field buffer is
            formatted according to the  printf  format  specification  ".*ld",
            where  the '*' is replaced by the precision argument.  For details
            of the precision handling see printf's man-page.

       TYPE_NUMERIC
            Numeric data (may have a decimal-point part). Requires a third int
            argument  controlling the precision, a fourth double argument con-
            straining minimum value, and a fifth double  constraining  maximum
            wide field, a regular expression "^[0-9]*$" always means that  you
            have to fill all eight positions with digits. If you want to allow
            fewer digits, you may use for example "^[0-9]* *$" which  is  good
            for  trailing  spaces  (up  to  an empty field), or "^ *[0-9]* *$"
            which is good for leading and trailing spaces around the digits.

       TYPE_IPV4
            An Internet Protocol Version 4 address.  This  requires  no  addi-
            tional  argument.  It is checked whether or not the buffer has the
            form a.b.c.d, where a,b,c and d are numbers  between  0  and  255.
            Trailing  blanks  in the buffer are ignored. The address itself is
            not validated. Please note that this is an ncurses extension. This
            field type may not be available in other curses implementations.

       It  is  possible to set up new programmer-defined field types.  See the
       form_fieldtype(3X) manual page.

RETURN VALUE

       The functions field_type and field_arg return NULL on error. The  func-
       tion set_field_type returns one of the following:

       E_OK The routine succeeded.

       E_SYSTEM_ERROR
            System error occurred (see errno).

SEE ALSO

       curses(3X), form(3X).

NOTES

       The  header  file  <form.h>  automatically  includes  the  header  file
       <curses.h>.

PORTABILITY

       These routines emulate the System V forms library.  They were not  sup-
       ported on Version 7 or BSD versions.

AUTHORS

       Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
       Raymond.



                                                     form_field_validation(3X)