form_fieldtype() -- define validation-field types

SYNOPSIS

#include <form.h>

FIELDTYPE *new_fieldtype( bool (* const field_check)(FIELD *, const void *), bool (* const char_check)(int, const void *)>);

int free_fieldtype(FIELDTYPE *fieldtype);

int set_fieldtype_arg( FIELDTYPE *fieldtype, void *(* const make_arg)(va_list *), void *(* const copy_arg)(const void *), void (* const free_arg)(void *));

int set_fieldtype_choice( FIELDTYPE *fieldtype, bool (* const next_choice)(FIELD *, const void *), bool (* const prev_choice)(FIELD *, const void *));

FIELDTYPE *link_fieldtype(FIELDTYPE *type1, FIELDTYPE *type2);

The function new_fieldtype() creates a new field type usable for data validation. You supply it with field_check, a predicate to check the validity of an entered data string whenever the user attempt to leave a field. The (FIELD *) argument is passed in so the validation predicate can see the field's buffer, sizes and other attributes; the second argument is an argument-block structure, about which more below.

You also supply new_fieldtype() with char_check, a function to validate input characters as they are entered; it will be passed the character to be checked and a pointer to an argument-block structure.

The function free_fieldtype() frees the space allocated for a given validation type.

The function set_fieldtype() associates three storage-management functions with a field type. The mak_arg function is automatically applied to the list of arguments you give set_field_type() when attaching validation to a field; its job is to bundle these into an allocated argument-block object which can later be passed to validation predicated. The other two hook arguments should copy and free argument-block structures. They will be used by the formsdriver code.

The form driver requests REQ_NEXT_CHOICE and REQ_PREV_CHOICE assume that the possible values of a field form an ordered set, and provide the forms user with a way to move through the set. The set_fieldtype_choice() function allows forms programmers to define successor and predecessor functions for the field type. These functions take the field pointer and an argument-block structure as arguments.

RETURN VALUES

The pointer-valued routines return NULL on error.

The integer-valued routines return one of the following codes on error:

E_OK: The routine succeeded.
E_SYSTEM_ERROR: System error occurred.
E_BAD_ARGUMENT: Routine detected an incorrect or out-of-range argument.
E_CONNECTED: The field is already connected to a form.

form_fieldtype()
define validation-field types

Curses Function

SYNOPSIS

DESCRIPTION

RETURN VALUES

NOTES

PORTABILITY

AUTHORS

AVAILABILITY

SEE ALSO

form_fieldtype() define validation-field types

Curses Function

form_fieldtype()
define validation-field types