NAME

       form_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(3)).

       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.

       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

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

                                                                              field_buffer(3FORM)