field_buffer(3form)

NAME

field_buffer - field buffer control

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

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 field_new(3FORM)) 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

The field_buffer function returns NULL on error. It sets errno according to their success:

E_OK The routine succeeded.

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 The routine succeeded.

E_SYSTEM_ERROR

System error occurred (see errno).

E_BAD_ARGUMENT

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

SEE ALSO

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

NOTES

The header file <form.h> automatically includes the header file

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. <curses.h>.

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.

field_buffer(3FORM)