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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | NOTES | PORTABILITY | AUTHORS | COLOPHON |
form_field_validation(3X) form_field_validation(3X)
form_field_validation - data type validation for fields
#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;
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.
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).
curses(3X), form(3X), form_variables(3X).
The header file <form.h> automatically includes the header file
<curses.h>.
These routines emulate the System V forms library. They were not
supported on Version 7 or BSD versions.
Juergen Pfeifer. Manual pages and adaptation for new curses by Eric
S. Raymond.
This page is part of the ncurses (new curses) project. Information
about the project can be found at
⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have a
bug report for this manual page, send it to
bug-ncurses-request@gnu.org. This page was obtained from the
project's upstream Git mirror of the CVS repository
⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2017-07-05. If you
discover any rendering problems in this HTML version of the page, or
you believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
to man-pages@man7.org
form_field_validation(3X)