.\"	$NetBSD: form_field_buffer.3,v 1.13 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.
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.Dd October 15, 2005
.Dt FORMS 3
.Os
.Sh NAME
.Nm field_buffer ,
.Nm field_status ,
.Nm set_field_buffer ,
.Nm set_field_printf ,
.Nm set_field_status ,
.Nm set_max_field
.Nd form library
.Sh LIBRARY
.Lb libform
.Sh SYNOPSIS
.In form.h
.Ft char *
.Fn field_buffer "FIELD *field" "int buffer"
.Ft int
.Fn field_status "FIELD *field"
.Ft int
.Fn set_field_buffer "FIELD *field" "int buffer" "char *value"
.Ft int
.Fn set_field_printf "FIELD *field" "int buffer" "char *fmt" "..."
.Ft int
.Fn set_field_status "FIELD *field" "int status"
.Ft int
.Fn set_max_field "FIELD *field" "int max"
.Sh DESCRIPTION
The
.Fn field_buffer
function returns the contents of the buffer number specified by
.Fa buffer
for the given field.
If the requested buffer number exceeds the
number of buffers attached to the field then
.Dv NULL
will be returned.
If the field option
.Dv O_REFORMAT
is enabled on the given field then
storage will be allocated to hold the reformatted buffer.
This storage must be release by calling
.Xr free 3
when it is no longer required.
If the
.Dv O_REFORMAT
field option is not set then no extra storage is allocated.
The field buffer may be set by calling
.Fn set_field_buffer
which will set the given buffer number to the contents of the string
passed.
A buffer may also be set by calling
.Fn set_field_printf
which sets the buffer using the format arg
.Fa fmt
after being expanded using the subsequent arguments in the same manner
as
.Xr sprintf 3
does.
Calling
.Fn field_status
will return the status of the first buffer attached to the field.
If the field has been modified then the function will return
.Dv TRUE
otherwise
.Dv FALSE
is returned, the status of the first buffer may be
programmatically set by calling
.Fn set_field_status .
The maximum growth of a dynamic field can be set by calling
.Fn set_max_field
which limits the fields rows if the field is a multiline field or the
fields columns if the field only has a single row.
.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.
.It Er E_BAD_ARGUMENT
A bad parameter was passed to the function.
.It Er E_SYSTEM_ERROR
A system error occurred performing the function.
.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 .
The function
.Fn set_field_printf
is a
.Nx
extension and must not be used in portable code.