управление буфером поля (field buffer control)
Имя (Name)
form_field_buffer - field buffer control
Синопсис (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);
Описание (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)) 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.
Возвращаемое значение (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(3)).
E_BAD_ARGUMENT
Routine detected an incorrect or out-of-range argument.
Смотри также (See also)
curses(3X) and related pages whose names begin 'form_' for
detailed descriptions of the entry points.
Примечание (Note)
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>.
Портативность (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.
