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SuSE 11.3 - man page for unctrl (suse section 3NCURSES)

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util(3NCURSES)									   util(3NCURSES)

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

SYNOPSIS
       #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);

DESCRIPTION
       The unctrl routine returns a character string which is a printable representation  of  the
       character  c,  ignoring	attributes.  Control characters are displayed in the ^X notation.
       Printing characters are displayed as is.  The corresponding wunctrl  returns  a	printable
       representation of a wide-character.

       The keyname routine returns a character string corresponding to the key c:

	  -  Printable	characters are displayed as themselves, e.g., a one-character string con-
	     taining the key.

	  -  Control characters are displayed in the ^X notation.

	  -  DEL (character 127) is displayed as ^?.

	  -  Values above 128 are either meta characters (if the screen has not been initialized,
	     or if meta has been called with a TRUE parameter), shown in the M-X notation, or are
	     displayed as themselves.  In the latter case, the values may not be printable;  this
	     follows the X/Open specification.

	  -  Values above 256 may be the names of the names of function keys.

	  -  Otherwise	(if  there is no corresponding name) the function returns null, to denote
	     an error.	X/Open also lists an "UNKNOWN KEY" return value, which	some  implementa-
	     tions return rather than 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 character.

       The filter routine, if used, must be called before initscr or newterm are called.  The ef-
       fect 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 call-
       er 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 argument, the values of lines and columns specified in the terminfo data-
       base will be used, even if environment variables LINES and COLUMNS (used by  default)  are
       set,  or  if curses is running in a window (in which case default behavior 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 program.

RETURN VALUE
       Except  for flushinp, routines that return an integer return ERR upon failure and OK (SVr4
       specifies only "an integer 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 implementation

	  flushinp
	       returns an error if the terminal was not initialized.

	  meta returns an error if the terminal was not initialized.

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

PORTABILITY
       The XSI Curses standard, Issue 4 describes these functions.  It	states	that  unctrl  and
       wunctrl	will  return a null pointer if unsuccessful, but does not define any error condi-
       tions.  This implementation checks for three cases:

	      -    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_lega-
		   cy_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.  Oth-
		   erwise, it returns ``~@'', ``~A'', etc., analogous to ``^@'', ``^A'', C0  con-
		   trols.

		   X/Open Curses does not document whether unctrl can be called before initializ-
		   ing 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 de-
       scription here is adapted from the XSI Curses standard (which  erroneously  fails  to  de-
       scribe 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 im-
       plementations 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 printable.  This implementation uses 8 bits but
       does not modify the string to reflect locale.  The use_legacy_coding function  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 after curses is initialized.  X/Open
       Curses does not document the treatment of  codes  128  to  159.	 When  treating  them  as
       ``meta''  keys  (or  if keyname is called before initializing 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 entry via the -x option of tic.	This implementation automatically
       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
       use_extended_names  function  controls  whether	this data is loaded when the terminal de-
       scription is read by the library.

       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 extensions
       be conditioned using NCURSES_VERSION.

SEE ALSO
       legacy_coding(3NCURSES),    ncurses(3NCURSES),	 initscr(3NCURSES),	kernel(3NCURSES),
       scr_dump(3NCURSES), legacy_coding(3NCURSES).

										   util(3NCURSES)
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