form_field_buffer 3x

form_field_buffer(3x)                             form_field_buffer(3x)

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 applica-
             tions   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  con-
       tents 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 win-
             dow  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 trail-
             ing 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 argu-
            ment.

       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  argu-
            ment.

SEE ALSO

       curses(3x) 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_buf-
       fer 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.



                                                  form_field_buffer(3x)