form_field_validation(3X) manual page
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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.
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