---
name: "form_sub"
section: "3x"
platform: "linux"
package: "ncurses"
version: "6.6-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/form_win/3x"
---

# form\_sub(3x)

make and break form window and subwindow associations

Part of [form\_win(3x)](/form_win/3x.md).

## NAME

**form\_win** - make and break form window and subwindow associations

## SYNOPSIS

```
#include <form.h>
```

**int set\_form\_win(FORM \****form***, WINDOW \****win***);** **WINDOW \*form\_win(const FORM \****form***);**

**int set\_form\_sub(FORM \****form***, WINDOW \****sub***);** **WINDOW \*form\_sub(const FORM \****form***);**

**int scale\_form(const FORM \****form***, int \****rows***, int \****columns***);**

## DESCRIPTION

**Every form has an associated pair of curses windows.** **The form window** **displays any title and border associated with the window; the form subwindow** **displays the items of the form that are currently available for selection.**

**The first four functions get and set those windows.** **It is not necessary to set** **either window; by default, the driver code uses stdscr for both.**

**In the set\_ functions, window argument of** *NULL* **is treated as though** **it were stsdcr.  A form argument of** *NULL* **is treated as a request** **to change the system default form window or subwindow.**

**The function scale\_form returns the minimum size required for the** **subwindow of** *form***.**

## RETURN VALUE

**Routines that return pointers return** *NULL* **on error.** **Routines that return** **an integer return one of the following error codes:**

- **E\_OK**

  **The routine succeeded.**

- **E\_SYSTEM\_ERROR**

  **System error occurred (see [errno(3)](/errno/3.md)).**

- **E\_BAD\_ARGUMENT**

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

- **E\_POSTED**

  **The form has already been posted.**

- **E\_NOT\_CONNECTED**

  **No items are connected to the form.**

## PORTABILITY

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

## AUTHORS

**Juergen Pfeifer.** **Manual pages and adaptation for new curses by Eric S. Raymond.**

## SEE ALSO

**curses(3X),** **curs\_variables(3X),** **form(3X)**