curs_util 3x

curs_util(3x)                                             curs_util(3x)


       delay_output, filter, flushinp, getwin, key_name, keyname,
       nofilter, putwin, unctrl, use_env, wunctrl - miscellaneous
       curses utility routines


       #include <curses.h>

       char *unctrl(chtype c);
       wchar_t *wunctrl(cchar_t *c);
       char *keyname(int c);
       char *key_name(wchar_t w);
       void filter(void);
       void nofilter(void);
       void use_env(bool f);
       int putwin(WINDOW *win, FILE *filep);
       WINDOW *getwin(FILE *filep);
       int delay_output(int ms);
       int flushinp(void);


       The  unctrl  routine returns a character string which is a
       printable representation of the character c, ignoring  at-
       tributes.   Control characters are displayed in the ^X no-
       tation.  Printing characters are  displayed  as  is.   The
       corresponding  wunctrl  returns a printable representation
       of a wide-character.

       The keyname routine returns a character string correspond-
       ing to the key c.  Control characters are displayed in the
       ^X notation.  Values above 128 are either meta characters,
       shown  in the M-X notation, or the names of function keys,
       or null.  The corresponding key_name returns  a  character
       string  corresponding  to the wide-character value w.  The
       two functions do not return the same set of  strings;  the
       latter  returns null where the former would display a meta

       The filter routine, if used, must be called before initscr
       or  newterm  are called.  The effect is that, during those
       calls, LINES is set to 1;  the  capabilities  clear,  cup,
       cud,  cud1,  cuu1,  cuu,  vpa  are  disabled; and the home
       string is set to the value of cr.

       The nofilter routine cancels the  effect  of  a  preceding
       filter  call.   That  allows  the  caller  to initialize a
       screen on a different device, using a different  value  of
       $TERM.   The  limitation arises because the filter routine
       modifies the in-memory copy of the terminal information.

       The use_env routine, if used, is called before initscr  or
       newterm  are  called.   When called with FALSE as an argu-
       ment, the values of lines and  columns  specified  in  the
       terminfo  database will be used, even if environment vari-
       ables LINES and COLUMNS (used by default) are set,  or  if
       curses  is  running in a window (in which case default be-
       havior would be to  use  the  window  size  if  LINES  and
       COLUMNS  are not set).  Note that setting LINES or COLUMNS
       overrides the corresponding size  which  may  be  obtained
       from the operating system.

       The  putwin routine writes all data associated with window
       win into the file to which filep points.  This information
       can be later retrieved using the getwin function.

       The getwin routine reads window related data stored in the
       file by putwin.  The routine then creates and  initializes
       a new window using that data.  It returns a pointer to the
       new window.

       The delay_output routine inserts an ms  millisecond  pause
       in  output.   This  routine should not be used extensively
       because padding characters are  used  rather  than  a  CPU
       pause.   If  no  padding character is specified, this uses
       napms to perform the delay.

       The flushinp routine throws away any  typeahead  that  has
       been  typed  by  the user and has not yet been read by the


       Except for flushinp, routines that return an  integer  re-
       turn  ERR upon failure and OK (SVr4 specifies only "an in-
       teger value other than ERR") upon successful completion.

       Routines that return pointers return NULL on error.

       X/Open does not define any error conditions.  In this  im-

                   returns  an error if the terminal was not ini-

                   returns an  error  if  the  associated  fwrite
                   calls return an error.


       The  XSI  Curses  standard,  Issue 4 describes these func-
       tions.  It states that unctrl and wunctrl  will  return  a
       null  pointer if unsuccessful, but does not define any er-
       ror conditions.  This implementation checks for three cas-

              -    the  parameter is a 7-bit US-ASCII code.  This
                   is the case that X/Open Curses documented.

              -    the parameter is in the range 128-159, i.e., a
                   C1  control  code.   If  use_legacy_coding has
                   been called with a 2 parameter, unctrl returns
                   the  parameter,  i.e.,  a one-character string
                   with the parameter  as  the  first  character.
                   Otherwise,  it  returns  ``~@'', ``~A'', etc.,
                   analogous to ``^@'', ``^A'', C0 controls.

                   X/Open Curses does not document whether unctrl
                   can  be  called  before  initializing  curses.
                   This implementation permits that, and  returns
                   the ``~@'', etc., values in that case.

              -    parameter  values  outside the 0 to 255 range.
                   unctrl returns a null pointer.

       The SVr4 documentation describes the action of filter only
       in  the  vaguest  terms.   The description here is adapted
       from the XSI Curses standard (which erroneously  fails  to
       describe the disabling of cuu).

       The  strings returned by unctrl in this implementation are
       determined at compile time, showing C1 controls  from  the
       upper-128  codes with a `~' prefix rather than `^'.  Other
       implementations have different conventions.  For  example,
       they  may  show  both sets of control characters with `^',
       and strip the parameter to 7 bits.  Or they may ignore  C1
       controls  and  treat  all of the upper-128 codes as print-
       able.  This implementation uses 8 bits but does not modify
       the string to reflect locale.  The use_legacy_coding func-
       tion allows the caller to change the output of unctrl.

       Likewise, the meta function allows the  caller  to  change
       the  output of keyname, i.e., it determines whether to use
       the `M-' prefix for ``meta'' keys (codes in the range  128
       to 255).  Both use_legacy_coding and meta succeed only af-
       ter curses is initialized.  X/Open Curses does  not  docu-
       ment  the  treatment  of  codes 128 to 159.  When treating
       them as ``meta'' keys (or if keyname is called before ini-
       tializing  curses),  this  implementation  returns strings
       ``M-^@'', ``M-^A'', etc.

       The keyname function may return the names of  user-defined
       string  capabilities which are defined in the terminfo en-
       try via the -x option of tic.  This  implementation  auto-
       matically  assigns  at  run-time  keycodes to user-defined
       strings which begin  with  "k".   The  keycodes  start  at
       KEY_MAX,  but  are not guaranteed to be the same value for
       different runs because user-defined codes are merged  from
       all terminal descriptions which have been loaded.

       The  nofilter  routine is specific to ncurses.  It was not
       supported on Version 7, BSD or System  V  implementations.
       It  is  recommended that any code depending on ncurses ex-
       tensions be conditioned using NCURSES_VERSION.


       legacy_coding(3x), curses(3x), curs_initscr(3x), curs_ker-
       nel(3x), curs_scr_dump(3x), legacy_coding(3x).


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