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FORMS(3) BSD Library Functions Manual FORMS(3)
form -- form library
Curses Form Library (libform, -lform)
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)
The form library provides facilities for defining form fields, placing a form on the termi-
nal 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 rou-
tine. 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
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
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.
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 char-
The TAB character The handling of the TAB character in fields varies between implementa-
tions. In ncurses attempting to set a field contents with a string con-
taining 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 cor-
rectly calculates the cursor position allowing for expansion of the TAB
set_field_printf This function is a NetBSD extension and must not be used in portable
O_REFORMAT This field option is a NetBSD extension and must not be used in portable
BSD November 24, 2004 BSD
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