lib/libform/forms.3

.\"	$NetBSD: forms.3,v 1.10 2002/10/01 19:15:17 wiz Exp $
.\"
.\" Copyright (c) 2001
.\"	Brett Lymn - blymn@baea.com.au, brett_lymn@yahoo.com.au
.\"
.\" This code is donated to The NetBSD Foundation by the author.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. The name of the Author may not be used to endorse or promote
.\"    products derived from this software without specific prior written
.\"    permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd January 1, 2001
.Dt FORMS 3
.Os
.Sh NAME
.Nm form
.Nd form library
.Sh LIBRARY
.Lb libform
.Sh SYNOPSIS
.Fd #include \*[Lt]form.h\*[Gt]
.Sh DESCRIPTION
The
.Nm
library provides a terminal independent form system using the
.Xr curses 3
library.
Before using the
.Nm
functions the terminal must be set up by
.Xr curses 3
using the
.Fn initscr
function or similar.
Programs using
.Nm
functions must be linked with the
.Xr curses 3
library
.Fl lcurses .
.Pp
The
.Nm
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.
.Ss Defining default attributes for forms and fields
The
.Nm
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.
.Pp
.ta 20
.nf
.ft 3
Form Routine Name      Manual Page Name
.sp 0.5
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)
.fi
.ft 1
.br
.ne 8
.Sh 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:
.Pp
.ta 20
.nf
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		An field was already connected to a form.
E_BAD_STATE		The function was called from within an initialisation
			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 recognise 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.
.fi
.ft 1
.br
.ne 8
.Sh SEE ALSO
.Xr curses 3 ,
.Xr menus 3
.Sh NOTES
This implementation of the forms library does depart in behaviour
subtly from the original AT \*[Am] T implementation.
Some of the more notable departures are:
.Pp
.Bl -tag -width "circular fields" -compact
.It field wrapping
For multiline fields the data will be wrapped as it is entered, this
does not happen in the AT\*[Am]T implementation.
.It buffer 0
In this implementation, the contents of buffer 0 are always current
regardless of whether the field has been validated or not.
.It circular fields
In the AT\*[Am]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
curent 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\*[Am]T it would result in the cursor being placed on the first field of
the first page.
.It buffer returns
In this implementation only the data entered by the user in the form
field will be returned, unlike the AT\*[Am]T library which would return the
contents of the field padded to the size of the field with the pad
character.
.It 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\*[Am]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.
.It set_field_printf
This function is a NetBSD extension and must not be used in portable
code.
.El