NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | NOTES | PORTABILITY | AUTHORS | COLOPHON

form_field_validation(3X)                          form_field_validation(3X)

NAME         top

       form_field_validation - data type validation for fields

SYNOPSIS         top

       #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         top

       The function set_field_type declares a data type for a given form
       field.  This is the type checked by validation functions.  The
       predefined 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 copied. So you may 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 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
            and regexec. 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(3X) manual page.

RETURN VALUE         top

       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
            System error occurred (see errno).

SEE ALSO         top

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

NOTES         top

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

PORTABILITY         top

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

AUTHORS         top

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

COLOPHON         top

       This page is part of the ncurses (new curses) project.  Information
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                                                   form_field_validation(3X)