.\"	$NetBSD: form_hook.3,v 1.10 2010/03/22 21:58:31 joerg 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
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.\"
.Dd January 1, 2001
.Dt FORMS 3
.Os
.Sh NAME
.Nm field_init ,
.Nm field_term ,
.Nm form_init ,
.Nm form_term ,
.Nm set_field_init ,
.Nm set_field_term ,
.Nm set_form_init ,
.Nm set_form_term
.Nd form library
.Sh LIBRARY
.Lb libform
.Sh SYNOPSIS
.In form.h
.Ft void (*)(FORM *)
.Fn field_init "FORM *form"
.Ft void (*)(FORM *)
.Fn field_term "FORM *form"
.Ft void (*)(FORM *)
.Fn form_init "FORM *form"
.Ft void (*)(FORM *)
.Fn form_term "FORM *form"
.Ft int
.Fn set_field_init "FORM *form" "void (*function)(FORM *)"
.Ft int
.Fn set_field_term "FORM *form" "void (*function)(FORM *)"
.Ft int
.Fn set_form_init "FORM *form" "void (*function)(FORM *)"
.Ft int
.Fn set_form_term "FORM *form" "void (*function)(FORM *)"
.Sh DESCRIPTION
The
.Fn field_init
function returns a pointer to the function that will be called just
after the current field changes and just before the form is posted,
this function may be set by using the
.Fn set_field_init
function.
Similarly, the function
.Fn field_term
will return a pointer to the function that will be called just before
the current field changes and just after the form is unposted, this
function pointer may be set by using the
.Fn set_field_term
function.
The
.Fn form_init
function will return a pointer to the function that will be called
just before the form is posted to the screen, this function can be set
by calling the
.Fn set_form_init
function.
The
.Fn form_term
function will return a pointer to the function that will be called
just after the form is unposted from the screen, this function may be
set by using the
.Fn set_form_term
function.
By default, the init and term function pointers are
.Dv NULL .
.Sh RETURN VALUES
Functions returning pointers will return
.Dv NULL
if an error is detected.
The functions that return an int will return one of the following error
values:
.Pp
.Bl -tag -width E_UNKNOWN_COMMAND -compact
.It Er E_OK
The function was successful.
.El
.Sh SEE ALSO
.Xr curses 3 ,
.Xr forms 3
.Sh NOTES
The header
.In form.h
automatically includes both
.In curses.h
and
.In eti.h .