NAME
form —
form library
LIBRARY
library “libform”
SYNOPSIS
#include
<form.h>
DESCRIPTION
Theform 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.
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:
SEE ALSO
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.