form - curses extension for programming forms
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.,
so that input/output processing will work.
A curses initialization routine such as initscr must be called before using any of these functions.
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.
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.
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.
curses(3X) and related pages whose names begin “form_” for detailed descriptions of the entry points.
This describes ncurses version 6.4 (patch 20221231).