field_type

form_field_validation(3X)                            form_field_validation(3X)



NAME
       form_field_validation - data type validation for fields

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

DESCRIPTION
       The  function  set_field_type  declares  a  data  type for a given form
       field.  This is the type checked by validation  functions.   The  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 to use 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 or equal the  minimum  value,
            the range is simply ignored. On return the field buffer is format-
            ted 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
            value. If your system supports locale's, the decimal point charac-
            ter to be used must be the one specified by your locale.   If  the
            maximum  value  is  less  or equal the minimum value, the range is
            simply ignored. On return the field buffer is formatted  according
            to  the  printf  format  specification  ".*f",  where  the  '*' is
            replaced by the precision argument.  For details of the  precision
            handling see printf's man-page.

       TYPE_REGEXP
            Regular  expression  data.  Requires a regular expression (char *)
            third argument; the  data  is  valid  if  the  regular  expression
            matches  it.  Regular expressions are in the format of regcomp(3X)
            and regexec(3X). Please notice that the  regular  expression  must
            match  the whole field. If you have for example an eight character
            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)