FORMS(3) Library Functions Manual FORMS(3)

NAME

form — form library

LIBRARY

Curses Form Library (libform, -lform)

SYNOPSIS

#include <form.h>

DESCRIPTION

The form library provides a terminal independent form system using the curses(3) library. Before using the form functions the terminal must be set up by curses(3) using the initscr() function or similar. Programs using form functions must be linked with the curses(3) library -lcurses.

The form library provides facilities for defining form fields, placing a form on the terminal screen, assign pre and post change operations and setting the attributes of both the form and its fields.

Defining default attributes for forms and fields

The form library allows any settable attribute or option of both the form and field objects to be defined such that any new form or field automatically inherits the value as default. Setting the default value will not affect any field or form that has already been created but will be applied to subsequent objects. To set the default attribute or option the set routine is passed a NULL pointer in the field or form parameter when calling the set routine. The current default value can be retrieved by calling the get routine with a NULL pointer for the field or form parameter.
Form Routine Name Manual Page Name
current_field form_page(3)
data_ahead form_data(3)
data_behind form_data(3)
dup_field form_field_new(3)
dynamic_field_info form_field_info(3)
field_arg form_field_validation(3)
field_back form_field_attributes(3)
field_buffer form_field_buffer(3)
field_count form_field(3)
field_fore form_field_attributes(3)
field_index form_page(3)
field_info form_field_info(3)
field_init form_hook(3)
field_just form_field_just(3)
field_opts form_field_opts(3)
field_opts_off form_field_opts(3)
field_opts_on form_field_opts(3)
field_pad form_field_attributes(3)
field_status form_field_buffer(3)
field_term form_hook(3)
field_type form_field_validation(3)
field_userptr form_field_userptr(3)
form_driver form_driver(3)
form_fields form_field(3)
form_init form_hook(3)
form_max_page form_page(3)
form_opts form_opts(3)
form_opts_off form_opts(3)
form_opts_on form_opts(3)
form_page form_page(3)
form_sub form_win(3)
form_term form_hook(3)
form_userptr form_userptr(3)
form_win form_win(3)
free_field form_field_new(3)
free_fieldtype form_fieldtype(3)
free_form form_new(3)
link_field form_field_new(3)
link_fieldtype form_fieldtype(3)
move_field form_field(3)
new_field form_field_new(3)
new_fieldtype form_fieldtype(3)
new_form form_new(3)
new_page form_new_page(3)
pos_form_cursor form_cursor(3)
post_form form_post(3)
scale_form form_win(3)
set_current_field form_page(3)
set_field_back form_field_attributes(3)
set_field_buffer form_field_buffer(3)
set_field_fore form_field_attributes(3)
set_field_init form_hook(3)
set_field_just form_field_just(3)
set_field_opts form_field_opts(3)
set_field_pad form_field_attributes(3)
set_field_printf form_field_buffer(3)
set_field_status form_field_buffer(3)
set_field_term form_hook(3)
set_field_type form_field_validation(3)
set_field_userptr form_field_userptr(3)
set_fieldtype_arg form_fieldtype(3)
set_fieldtype_choice form_fieldtype(3)
set_form_fields form_field(3)
set_form_init form_hook(3)
set_form_opts form_opts(3)
set_form_page form_page(3)
set_form_sub form_win(3)
set_form_term form_hook(3)
set_form_userptr form_userptr(3)
set_form_win form_win(3)
set_max_field form_field_buffer(3)
set_new_page form_new_page(3)
unpost_form form_post(3)

RETURN VALUES

Any function returning a string pointer will return NULL if an error occurs. Functions returning an integer will return one of the following:
E_OK The function was successful.
E_SYSTEM_ERROR There was a system error during the call.
E_BAD_ARGUMENT One or more of the arguments passed to the function was incorrect.
E_POSTED The form is already posted.
E_CONNECTED A field was already connected to a form.
E_BAD_STATE The function was called from within an initialization or termination routine.
E_NO_ROOM The form does not fit within the subwindow.
E_NOT_POSTED The form is not posted.
E_UNKNOWN_COMMAND The form driver does not recognize the request passed to it.
E_NOT_SELECTABLE The field could not be selected.
E_NOT_CONNECTED The field is not connected to a form.
E_REQUEST_DENIED The form driver could not process the request.
E_INVALID_FIELD The field is invalid.
E_CURRENT The field is the active one on the form.

SEE ALSO

curses(3), menus(3)

NOTES

This implementation of the forms library does depart in behavior subtly from the original AT&T implementation. Some of the more notable departures are:

field wrapping
For multi-line fields the data will be wrapped as it is entered, this does not happen in the AT&T implementation.
buffer 0
In this implementation, the contents of buffer 0 are always current regardless of whether the field has been validated or not.
circular fields
In the AT&T implementation fields are circular on a page, that is, a next field from the last field will go to the first field on the current page. In this implementation a next field request on the last field of a page will result in the forms library positioning the cursor on the first field of the next page. If the field is the last field in the form then going to the next field will be denied, in the AT&T it would result in the cursor being placed on the first field of the first page.
buffer returns
In this implementation only the data entered by the user in the form field will be returned, unlike the AT&T library which would return the contents of the field padded to the size of the field with the pad character.
The TAB character
The handling of the TAB character in fields varies between implementations. In ncurses attempting to set a field contents with a string containing a TAB will result in an error and will not allow a TAB to be entered into a field. The AT&T library statically converts tabs to the equivalent number of spaces when the field buffer is set but the form driver will not allow a TAB to be inserted into the field buffer. This implementation allows TAB when setting the field buffer and also will allow TAB to be inserted into a field buffer via the form driver and correctly calculates the cursor position allowing for expansion of the TAB character.
set_field_printf
This function is a NetBSD extension and must not be used in portable code.
O_REFORMAT
This field option is a NetBSD extension and must not be used in portable code.
November 24, 2004 NetBSD 6.1