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form(3FORM) form(3FORM)


form - curses extension for programming forms


#include <form.h>


The form library provides terminal-independent facilities for composing form screens on character-cell terminals. The library includes: field routines, which create and modify form fields; and form routines, which group fields into forms, display forms on the screen, and handle interaction with the user.

The form library uses the curses libraries. To use the form library, link with the options -lform -lcurses.

Your program should set up the locale, e.g.,

setlocale(LC_ALL, "");

so that input/output processing will work.

A curses initialization routine such as initscr must be called before using any of these functions.

Current Default Values for Field Attributes

The form library maintains a default value for field attributes. You can get or set this default by calling the appropriate set_ or retrieval routine with a NULL field pointer. Changing this default with a set_ function affects future field creations, but does not change the rendering of fields already created.

Routine Name Index

The following table lists each form routine and the name of the manual page on which it is described. Routines flagged with “*” are ncurses-specific, not present in SVr4.

curses Routine Name Manual Page Name
current_field page(3FORM)
data_ahead data(3FORM)
data_behind data(3FORM)
dup_field field_new(3FORM)
dynamic_field_info field_info(3FORM)
field_arg field_validation(3FORM)
field_back field_attributes(3FORM)
field_buffer field_buffer(3FORM)
field_count field(3FORM)
field_fore field_attributes(3FORM)
field_index page(3FORM)
field_info field_info(3FORM)
field_init hook(3FORM)
field_just field_just(3FORM)
field_opts field_opts(3FORM)
field_opts_off field_opts(3FORM)
field_opts_on field_opts(3FORM)
field_pad field_attributes(3FORM)
field_status field_buffer(3FORM)
field_term hook(3FORM)
field_type field_validation(3FORM)
field_userptr field_userptr(3FORM)
form_driver driver(3FORM)
form_driver_w driver(3FORM)*
form_fields field(3FORM)
form_init hook(3FORM)
form_opts opts(3FORM)
form_opts_off opts(3FORM)
form_opts_on opts(3FORM)
form_page page(3FORM)
form_request_by_name requestname(3FORM)*
form_request_name requestname(3FORM)*
form_sub win(3FORM)
form_term hook(3FORM)
form_userptr userptr(3FORM)
form_win win(3FORM)
free_field field_new(3FORM)
free_fieldtype fieldtype(3FORM)
free_form new(3FORM)
link_field field_new(3FORM)
link_fieldtype fieldtype(3FORM)
move_field field(3FORM)
new_field field_new(3FORM)
new_fieldtype fieldtype(3FORM)
new_form new(3FORM)
new_page new_page(3FORM)
pos_form_cursor cursor(3FORM)
post_form post(3FORM)
scale_form win(3FORM)
set_current_field page(3FORM)
set_field_back field_attributes(3FORM)
set_field_buffer field_buffer(3FORM)
set_field_fore field_attributes(3FORM)
set_field_init hook(3FORM)
set_field_just field_just(3FORM)
set_field_opts field_opts(3FORM)
set_field_pad field_attributes(3FORM)
set_field_status field_buffer(3FORM)
set_field_term hook(3FORM)
set_field_type field_validation(3FORM)
set_field_userptr field_userptr(3FORM)
set_fieldtype_arg fieldtype(3FORM)
set_fieldtype_choice fieldtype(3FORM)
set_form_fields field(3FORM)
set_form_init hook(3FORM)
set_form_opts field_opts(3FORM)
set_form_page page(3FORM)
set_form_sub win(3FORM)
set_form_term hook(3FORM)
set_form_userptr userptr(3FORM)
set_form_win win(3FORM)
set_max_field field_buffer(3FORM)
set_new_page new_page(3FORM)
unfocus_current_field page(3FORM)*
unpost_form post(3FORM)


Routines that return pointers return NULL on error, and set errno to the corresponding error-code returned by functions returning an integer. Routines that return an integer return one of the following error codes:

The routine succeeded.
Routine detected an incorrect or out-of-range argument.
Routine was called from an initialization or termination function.
The field is already connected to a form.
Contents of a field are not valid.
No fields are connected to the form.
The form has not been posted.
Form is too large for its window.
The form is already posted.
The form driver could not process the request.
System error occurred (see errno(3)).
The form driver code saw an unknown request code.


The header file <form.h> automatically includes the header files <curses.h> and <eti.h>.

In your library list, libform.a should be before libncurses.a; that is, you want to say “-lform -lncurses”, not the other way around (which would give you a link error when using static libraries).


These routines emulate the System V forms library. They were not supported on Version 7 or BSD versions.

The menu facility was documented in SVr4.2 in Character User Interface Programming (UNIX SVR4.2).

It is not part of X/Open Curses.

Aside from ncurses, there are few implementations:

  • systems based on SVr4 source code, e.g., Solaris.
  • NetBSD curses.

A few functions in this implementation are extensions added for ncurses, but not provided by other implementations, e.g., form_driver_w, unfocus_current_field.


Juergen Pfeifer. Manual pages and adaptation for ncurses by Eric S. Raymond.


ncurses(3NCURSES) and related pages whose names begin “form_” for detailed descriptions of the entry points.

This describes ncurses version 6.4 (patch 20221231).