- The unctrl macro expands to a character string which is a
- printable representation of the character c. Control
- characters are displayed in the ^X notation. Printing
- characters are displayed as is.
+
+ 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.
- 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 keyname routine returns a character string correspond-
+ ing to the key c:
- 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
- behavior would be to use the window size if LINES and
- COLUMNS are not set).
+ o Printable characters are displayed as themselves,
+ e.g., a one-character string containing the key.
- 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.
+ o Control characters are displayed in the ^X notation.
- 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.
+ o DEL (character 127) is displayed as ^?.
- 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.
- The flushinp routine throws away any typeahead that has
- been typed by the user and has not yet been read by the
- program.
+ o 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 nota-
+ tion, or are displayed as themselves. In the latter
+ case, the values may not be printable; this follows
+ the X/Open specification.
+ o Values above 256 may be the names of the names of
+ function keys.
-
-
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.
+ o Otherwise (if there is no corresponding name) the
+ function returns null, to denote an error. X/Open al-
+ so lists an "UNKNOWN KEY" return value, which some im-
+ plementations return rather than null.
+
+ The corresponding key_name returns a character string cor-
+ responding to the wide-character value w. The two func-
+ tions do not return the same set of strings; the latter
+ returns null where the former would display a meta charac-
+ ter.
- flushinp always returns OK.
- Routines that return pointers return NULL on error.
+
+ 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.
-
PORTABILITY
- The XSI Curses standard, Issue 4 describes these func-
- tions.
+
+ The use_env routine, if used, should be called before
+ initscr or newterm are called (because those compute the
+ screen size). It modifies the way ncurses treats environ-
+ ment variables when determining the screen size.
+
+ o Normally ncurses looks first at the terminal database
+ for the screen size.
+
+ If use_env was called with FALSE for parameter, it
+ stops here unless If use_tioctl was also called with
+ TRUE for parameter.
+
+ o Then it asks for the screen size via operating system
+ calls. If successful, it overrides the values from
+ the terminal database.
+
+ o Finally (unless use_env was called with FALSE parame-
+ ter), ncurses examines the LINES or COLUMNS environ-
+ ment variables, using a value in those to override the
+ results from the operating system or terminal data-
+ base.
- 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).
+ Ncurses also updates the screen size in response to
+ SIGWINCH, unless overridden by the LINES or COLUMNS
+ environment variables,
-
NOTES
- Note that unctrl is a macro, which is defined in <unc-
- trl.h>.
+
+ The use_tioctl routine, if used, should be called before
+ initscr or newterm are called (because those compute the
+ screen size). After use_tioctl is called with TRUE as an
+ argument, ncurses modifies the last step in its computa-
+ tion of screen size as follows:
+
+ o checks if the LINES and COLUMNS environment variables
+ are set to a number greater than zero.
+
+ o for each, ncurses updates the corresponding environ-
+ ment variable with the value that it has obtained via
+ operating system call or from the terminal database.
+
+ o ncurses re-fetches the value of the environment vari-
+ ables so that it is still the environment variables
+ which set the screen size.
+
+ The use_env and use_tioctl routines combine as summarized
+ here:
+
+ use_envuse_tioctlSummary
+ ----------------------------------------------------------------
+
+
+
+ TRUE FALSE This is the default behavior. ncurses
+ uses operating system calls unless over-
+ ridden by $LINES or $COLUMNS environment
+ variables.
+ TRUE TRUE ncurses updates $LINES and $COLUMNS
+ based on operating system calls.
+ FALSE TRUE ncurses ignores $LINES and $COLUMNS, us-
+ es operating system calls to obtain
+ size.
+ FALSE FALSE ncurses relies on the terminal database
+ to determine size.
+ The putwin routine writes all data associated with window
+ (or pad) win into the file to which filep points. This
+ information can be later retrieved using the getwin func-
+ tion.
+
+ 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. There are a few caveats:
+ o the data written is a copy of the WINDOW structure,
+ and its associated character cells. The format dif-
+ fers between the wide-character (ncursesw) and non-
+ wide (ncurses) libraries. You can transfer data be-
+ tween the two, however.
+ o the retrieved window is always created as a top-level
+ window (or pad), rather than a subwindow.
+ o the window's character cells contain the color pair
+ value, but not the actual color numbers. If cells in
+ the retrieved window use color pairs which have not
+ been created in the application using init_pair, they
+ will not be colored when the window is refreshed.
+
+ 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.
+
+ 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-
+ plementation
+ flushinp
+ returns an error if the terminal was not initial-
+ ized.
+ meta returns an error if the terminal was not initial-
+ ized.
+ putwin
+ returns an error if the associated fwrite calls
+ return an error.
+
+ 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 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
+ use_extended_names function controls whether this data is
+ loaded when the terminal description is read by the li-
+ brary.
+
+ The nofilter and use_tioctl routines are specific to
+ ncurses. They were 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.
+
+ The putwin and getwin functions have several issues with
+ portability:
+
+ o The files written and read by these functions use an
+ implementation-specific format. Although the format
+ is an obvious target for standardization, it has been
+ overlooked.
+
+ Interestingly enough, according to the copyright dates
+ in Solaris source, the functions (along with scr_init,
+ etc.) originated with the University of California,
+ Berkeley (in 1982) and were later (in 1988) incorpo-
+ rated into SVr4. Oddly, there are no such functions
+ in the 4.3BSD curses sources.
+
+ o Most implementations simply dump the binary WINDOW
+ structure to the file. These include SVr4 curses,
+ NetBSD and PDCurses, as well as older ncurses ver-
+ sions. This implementation (as well as the X/Open
+ variant of Solaris curses, dated 1995) uses textual
+ dumps.
+
+ The implementations which use binary dumps use block-
+ I/O (the fwrite and fread functions). Those that use
+ textual dumps use buffered-I/O. A few applications
+ may happen to write extra data in the file using these
+ functions. Doing that can run into problems mixing
+ block- and buffered-I/O. This implementation reduces
+ the problem on writes by flushing the output. Howev-
+ er, reading from a file written using mixed schemes
+ may not be successful.
+
+ 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-
+ es:
+
+ o the parameter is a 7-bit US-ASCII code. This is the
+ case that X/Open Curses documented.
+
+ o the parameter is in the range 128-159, i.e., a C1 con-
+ trol 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 implementa-
+ tion permits that, and returns the "~@", etc., values
+ in that case.
+
+ o parameter values outside the 0 to 255 range. unctrl
+ returns a null pointer.
+
+ 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 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.
+