form\_field\_buffer(3X) Library calls form\_field\_buffer(3X)

# [NAME](#NAME)

**form\_field\_buffer** - field buffer control

# [SYNOPSIS](#SYNOPSIS)

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

```
int set_field_buffer(FIELD *field, int buf, const char *value);
char *field_buffer(const FIELD *field, int buffer);
```

```
int set_field_status(FIELD *field, bool status);
bool field_status(const FIELD *field);
```

```
int set_max_field(FIELD *field, int max);
```

# [DESCRIPTION](#DESCRIPTION)

The function **set\_field\_buffer** sets the numbered buffer of the given field to contain a given string:

- Buffer 0 is the displayed value of the field.
- Other numbered buffers may be allocated by applications through the **nbuf** argument of (see [**form\_field\_new**(3X)](/man/os/ncurses/form_field_new.3X)) but are not manipulated by the forms library.

The function **field\_buffer** returns a pointer to the contents of the given numbered buffer:

- The buffer contents always have the same length, and are padded with trailing spaces as needed to ensure this length is the same.
- The buffer may contain leading spaces, depending on how it was set.
- The buffer contents are set with **set\_field\_buffer**, or as a side effect of any editing operations on the corresponding field.
- Editing operations are based on the *window* which displays the field, rather than a *string*. The window contains only printable characters, and is filled with blanks. If you want the raw data, you must write your own routine that copies the value out of the buffer and removes the leading and trailing spaces.
- Because editing operations change the content of the buffer to correspond to the window, you should not rely on using buffers for long-term storage of form data.

The function **set\_field\_status** sets the associated status flag of *field*; **field\_status** gets the current value. The status flag is set to a nonzero value whenever the field changes.

The function **set\_max\_field** sets the maximum size for a dynamic field. An argument of 0 turns off any maximum size threshold for that field.

# [RETURN VALUE](#RETURN_VALUE)

The **field\_buffer** function returns *NULL* on error. It sets **errno** according to their success:

[**E\_OK**](#E_OK)

The routine succeeded.

[**E\_BAD\_ARGUMENT**](#E_BAD_ARGUMENT)

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

The **field\_status** function returns **TRUE** or **FALSE**.

The remaining routines return one of the following:

[**E\_OK**](#E_OK~2)

The routine succeeded.

[**E\_SYSTEM\_ERROR**](#E_SYSTEM_ERROR)

System error occurred (see [**errno**(3)](/man/os/ncurses/errno.3)).

[**E\_BAD\_ARGUMENT**](#E_BAD_ARGUMENT~2)

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

# [NOTES](#NOTES)

When configured for wide characters, **field\_buffer** returns a pointer to temporary storage (allocated and freed by the library). The application should not attempt to modify the data. It will be freed on the next call to **field\_buffer** to return the same buffer.

# [PORTABILITY](#PORTABILITY)

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

The **set\_max\_field** function checks for an *ncurses* extension **O\_INPUT\_FIELD** which allows a dynamic field to shrink if the new limit is smaller than the current field size.

# [AUTHORS](#AUTHORS)

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

# [SEE ALSO](#SEE_ALSO)

[**curses**(3X)](/man/os/ncurses/curses.3X) and related pages whose names begin “form\_” for detailed descriptions of the entry points.

2024-12-28 ncurses 6.6

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Document: set_field_buffer(3x) from ncurses 6.6.20261010-r0 (Chainguard OS)
Source: https://github.com/ThomasDickey/ncurses-snapshots