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.
+ of a wide character.
The keyname routine returns a character string correspond-
ing to the key c:
- - Printable characters are displayed as themselves,
- e.g., a one-character string containing the key.
+ o Printable characters are displayed as themselves,
+ e.g., a one-character string containing the key.
- - Control characters are displayed in the ^X notation.
+ o Control characters are displayed in the ^X nota-
+ tion.
- - DEL (character 127) is displayed as ^?.
+ o 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 no-
- tation, or are displayed as themselves. In the lat-
- ter case, the values may not be printable; this fol-
- lows the X/Open specification.
+ 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 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.
+ o 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
- implementations return rather than null.
+ o 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 implementations return rather than null.
The corresponding key_name returns a character string cor-
responding to the wide-character value w. The two func-
@@ -121,16 +125,66 @@
$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 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.
+
+ Ncurses also updates the screen size in response to
+ SIGWINCH, unless overridden by the LINES or COLUMNS
+ environment variables,
+
+ 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
win into the file to which filep points. This information
@@ -153,7 +207,7 @@
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.
@@ -163,41 +217,43 @@
X/Open does not define any error conditions. In this im-
plementation
- flushinp
- returns an error if the terminal was not ini-
- tialized.
+ flushinp
+ returns an error if the terminal was not initial-
+ ized.
- putwin
- returns an error if the associated fwrite
- calls return an error.
+ meta returns an error if the terminal was not initial-
+ ized.
+
+ putwin
+ returns an error if the associated fwrite calls
+ return an error.
-
PORTABILITY
- 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-
+
+ 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:
- - the parameter is a 7-bit US-ASCII code. This
- is the case that X/Open Curses documented.
+ o 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.
+ o 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.
+ X/Open Curses does not document whether unctrl can
+ be called before initializing curses. This imple-
+ mentation permits that, and returns the "~@", etc.,
+ values in that case.
- - parameter values outside the 0 to 255 range.
- unctrl returns a null pointer.
+ o parameter values outside the 0 to 255 range. unc-
+ trl returns a null pointer.
The SVr4 documentation describes the action of filter only
in the vaguest terms. The description here is adapted
@@ -217,13 +273,13 @@
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 `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 en-
@@ -237,25 +293,32 @@
loaded when the terminal description is read by the li-
brary.
- 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.
+ 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.