NAME    [Toc]    [Back]

       form_field_validation - data type validation for fields

SYNOPSIS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

       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  specifying  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  constraining  minimum
            value, and a fifth double constraining maximum value.
            If your system supports locales,  the  decimal  point
            character  to  be  used  must be the one specified by
            your locale.  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 ".*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(3) and regexec(3).
            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  additional 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(3) manual page.

RETURN VALUE    [Toc]    [Back]

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


       E_OK The routine succeeded.

       E_SYSTEM_ERROR    [Toc]    [Back]
            System error occurred (see errno).

SEE ALSO    [Toc]    [Back]

       curses(3), form(3).

NOTES    [Toc]    [Back]

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

PORTABILITY    [Toc]    [Back]

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

AUTHORS    [Toc]    [Back]

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