# form 3x 2023-12-23 ncurses 6.4 Library calls

    form(3x)                         Library calls                        form(3x)

## NAME

           form - curses extension for programming forms

## SYNOPSIS

           #include <form.h>

## DESCRIPTION

           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           form_page(3x)
           data_ahead              form_data(3x)
           data_behind             form_data(3x)
           dup_field               form_field_new(3x)
           dynamic_field_info      form_field_info(3x)
           field_arg               form_field_validation(3x)
           field_back              form_field_attributes(3x)
           field_buffer            form_field_buffer(3x)
           field_count             form_field(3x)
           field_fore              form_field_attributes(3x)
           field_index             form_page(3x)
           field_info              form_field_info(3x)
           field_init              form_hook(3x)
           field_just              form_field_just(3x)
           field_opts              form_field_opts(3x)
           field_opts_off          form_field_opts(3x)
           field_opts_on           form_field_opts(3x)
           field_pad               form_field_attributes(3x)
           field_status            form_field_buffer(3x)
           field_term              form_hook(3x)
           field_type              form_field_validation(3x)
           field_userptr           form_field_userptr(3x)

           form_driver             form_driver(3x)
           form_driver_w           form_driver(3x)*
           form_fields             form_field(3x)
           form_init               form_hook(3x)
           form_opts               form_opts(3x)
           form_opts_off           form_opts(3x)
           form_opts_on            form_opts(3x)
           form_page               form_page(3x)
           form_request_by_name    form_requestname(3x)*
           form_request_name       form_requestname(3x)*
           form_sub                form_win(3x)
           form_term               form_hook(3x)
           form_userptr            form_userptr(3x)
           form_win                form_win(3x)
           free_field              form_field_new(3x)
           free_fieldtype          form_fieldtype(3x)
           free_form               form_new(3x)
           link_field              form_field_new(3x)
           link_fieldtype          form_fieldtype(3x)
           move_field              form_field(3x)
           new_field               form_field_new(3x)
           new_fieldtype           form_fieldtype(3x)
           new_form                form_new(3x)
           new_page                form_new_page(3x)
           pos_form_cursor         form_cursor(3x)
           post_form               form_post(3x)
           scale_form              form_win(3x)
           set_current_field       form_page(3x)
           set_field_back          form_field_attributes(3x)
           set_field_buffer        form_field_buffer(3x)
           set_field_fore          form_field_attributes(3x)
           set_field_init          form_hook(3x)
           set_field_just          form_field_just(3x)
           set_field_opts          form_field_opts(3x)
           set_field_pad           form_field_attributes(3x)
           set_field_status        form_field_buffer(3x)
           set_field_term          form_hook(3x)
           set_field_type          form_field_validation(3x)
           set_field_userptr       form_field_userptr(3x)
           set_fieldtype_arg       form_fieldtype(3x)
           set_fieldtype_choice    form_fieldtype(3x)
           set_form_fields         form_field(3x)
           set_form_init           form_hook(3x)
           set_form_opts           form_field_opts(3x)
           set_form_page           form_page(3x)
           set_form_sub            form_win(3x)
           set_form_term           form_hook(3x)
           set_form_userptr        form_userptr(3x)
           set_form_win            form_win(3x)
           set_max_field           form_field_buffer(3x)
           set_new_page            form_new_page(3x)
           unfocus_current_field   form_page(3x)*
           unpost_form             form_post(3x)

## RETURN VALUE

           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:

           E_OK The routine succeeded.

           E_BAD_ARGUMENT
                Routine detected an incorrect or out-of-range argument.

           E_BAD_STATE
                Routine was called from an initialization or termination function.

           E_CONNECTED
                The field is already connected to a form.

           E_INVALID_FIELD
                Contents of a field are not valid.

           E_NOT_CONNECTED
                No fields are connected to the form.

           E_NOT_POSTED
                The form has not been posted.

           E_NO_ROOM
                Form is too large for its window.

           E_POSTED
                The form is already posted.

           E_REQUEST_DENIED
                The form driver could not process the request.

           E_SYSTEM_ERROR
                System error occurred (see errno(3)).

           E_UNKNOWN_COMMAND
                The form driver code saw an unknown request code.

## NOTES

           The header file form.h itself includes curses.h.

## PORTABILITY

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

           A  form  facility  was  documented in SVr4.2's Character User Interface
           Programming document.

           It is not part of X/Open Curses.

           Aside from ncurses, there are few implementations:

           o   systems based on SVr4 source code, e.g., Solaris.

           o   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.

## AUTHORS

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

## SEE ALSO

           curses(3x)  and  related  pages  whose names begin "form_" for detailed
           descriptions of the entry points.

    ncurses 6.4                       2023-12-23                          form(3x)