- The unctrl routine returns a character string which is a printable rep-
- resentation of the character c, ignoring attributes. Control charac-
- ters are displayed in the ^X notation. Printing characters are dis-
- played as is. The corresponding wunctrl returns a printable represen-
- tation of a wide character.
-
-
-
- The keyname routine returns a character string corresponding to the key
- c:
+ The unctrl routine returns a character string which is a printable
+ representation of the character ch:
- o Printable characters are displayed as themselves, e.g., a one-char-
- acter string containing the key.
+ o Printable characters are displayed as themselves, e.g., a one-
+ character string containing the key.
o Control characters are displayed in the ^X notation.
+ o Printing characters are displayed as is.
+
o DEL (character 127) is displayed as ^?.
o Values above 128 are either meta characters (if the screen has not
- been initialized, or if meta(3x) has been called with a TRUE param-
- eter), 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.
+ been initialized, or if meta(3x) 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.
+
+ The corresponding wunctrl returns a printable representation of a
+ complex character wch.
+
+ In both unctrl and wunctrl the attributes and color associated with the
+ character parameter are ignored.
+
+
+
+ The keyname routine returns a character string corresponding to the key
+ c. Key codes are different from character codes.
- o Values above 256 may be the names of the names of function keys.
+ o Key codes below 256 are characters. They are displayed using
+ unctrl.
- o Otherwise (if there is no corresponding name) the function returns
- null, to denote an error. X/Open also lists an "UNKNOWN KEY" re-
- turn value, which some implementations return rather than null.
+ o Values above 256 may be the codes for function keys. The function
+ key name is displayed.
- 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.
+ o Otherwise (if there is no corresponding name and the key is not a
+ character) 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 multibyte character string
+ corresponding to the wide-character value w. The two functions
+ (keyname and key_name) do not return the same set of strings:
-
- The filter routine, if used, must be called before initscr or newterm
+ okeyname returns null where key_name would display a meta character.
+
+ okey_name does not return the name of a function key.
+
+
+
+ The filter routine, if used, must be called before initscr or newterm
are called. Calling filter causes these changes in initialization:
oLINES is set to 1;
- o the capabilities clear, cud1, cud, cup, cuu1, cuu, vpa are dis-
- abled;
+ o the capabilities clear, cud1, cud, cup, cuu1, cuu, vpa are
+ disabled;
o the capability ed is disabled if bce is set;
o 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
+ 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, should be called before initscr or
- newterm are called (because those compute the screen size). It modi-
- fies the way ncurses treats environment variables when determining the
- screen size.
+ 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 environment variables when determining
+ the screen size.
- o Normally ncurses looks first at the terminal database for the
+ 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 un-
- less use_tioctl was also called with TRUE for parameter.
+ If use_env was called with FALSE for parameter, it stops here
+ unless use_tioctl was also called with TRUE for parameter.
- o Then it asks for the screen size via operating system calls. If
+ 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 parameter), ncurses
- examines the LINES or COLUMNS environment variables, using a value
- in those to override the results from the operating system or ter-
- minal database.
+ o Finally (unless use_env was called with FALSE parameter), ncurses
+ examines the LINES or COLUMNS environment variables, using a value
+ in those to override the results from the operating system or
+ terminal database.
- Ncurses also updates the screen size in response to SIGWINCH, un-
- less overridden by the LINES or COLUMNS environment variables,
+ curses 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
+ 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 computation of screen size as follows:
- o checks if the LINES and COLUMNS environment variables are set to a
+ o checks if the LINES and COLUMNS environment variables are set to a
number greater than zero.
- o for each, ncurses updates the corresponding environment variable
- with the value that it has obtained via operating system call or
+ o for each, ncurses updates the corresponding environment variable
+ with the value that it has obtained via operating system call or
from the terminal database.
- oncurses re-fetches the value of the environment variables so that
+ oncurses re-fetches the value of the environment variables so that
it is still the environment variables which set the screen size.
- The use_env and use_tioctl routines combine as summarized here:
+ The use_env and use_tioctl routines combine as follows.
- use_envuse_tioctlSummary
- ----------------------------------------------------------------
- TRUE FALSE This is the default behavior. ncurses
- uses operating system calls unless over-
- ridden by $LINES or $COLUMNS environment
- variables.
+ use_envuse_tioctlSummary
+ -----------------------------------------------------------------
+ TRUEFALSEncurses uses operating system calls
+ unless overridden by LINES or COLUMNS
+ environment variables; default.
+ TRUETRUEncurses updates LINES and COLUMNS based
+ on operating system calls.
+ FALSETRUEncurses ignores LINES and COLUMNS, using
+ operating system calls to obtain size.
- 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 re-
- trieved using the getwin function.
+ 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. There are a few
caveats:
- o the data written is a copy of the WINDOW structure, and its associ-
- ated character cells. The format differs between the wide-charac-
- ter (ncursesw) and non-wide (ncurses) libraries. You can transfer
- data between the two, however.
+ o the data written is a copy of the WINDOW structure, and its
+ associated character cells. The format differs between the wide-
+ character (ncursesw) and non-wide (ncurses) libraries. You can
+ transfer data between the two, however.
o the retrieved window is always created as a top-level window (or
pad), rather than a subwindow.
@@ -217,101 +227,124 @@
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 speci-
- fied, this uses napms to perform the delay.
+ Employ this function judiciously when terminal output uses padding,
+ because ncurses transmits null characters (consuming CPU and I/O
+ resources) instead of sleeping and requesting resumption from the
+ operating system. Padding is used unless:
+
+ o the terminal description has npc (no_pad_char) capability, or
+
+ o the environment variable NCURSES_NO_PADDING is set.
+
+ If padding is not in use, ncurses uses napms to perform the delay. If
+ the value of ms exceeds 30,000 (thirty seconds), it is capped at that
+ value.
- The flushinp routine throws away any typeahead that has been typed by
+ The flushinp routine throws away any typeahead that has been typed by
the user and has not yet been read by the program.
- Except for flushinp, routines that return an integer return ERR upon
- failure and OK (SVr4 specifies only "an integer value other than ERR")
+ 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
+ X/Open Curses does not specify any error conditions. In this
+ implementation
flushinp
returns an error if the terminal was not initialized.
putwin
- returns an error if the associated fwrite calls return an er-
- ror.
+ 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).
+ vaguest terms. The description here is adapted from X/Open Curses
+ (which erroneously fails to describe the disabling of cuu).
+
+
+
+ The limitation to 30 seconds and the use of napms differ from other
+ implementations.
+
+ o SVr4 curses does not delay if no padding character is available.
+
+ o NetBSD curses uses napms when no padding character is available,
+ but does not take timing into account when using the padding
+ character.
+
+ Neither limits the delay.
- The keyname function may return the names of user-defined string capa-
- bilities 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
+ 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(3x) function controls
- whether this data is loaded when the terminal description is read by
+ because user-defined codes are merged from all terminal descriptions
+ which have been loaded. The use_extended_names(3x) function controls
+ whether this data is loaded when the terminal description is read by
the library.
-
- 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 condi-
- tioned 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.
-
The putwin and getwin functions have several issues with portability:
- o The files written and read by these functions use an implementa-
- tion-specific format. Although the format is an obvious target for
- standardization, it has been overlooked.
+ 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
+ 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) incorporated into SVr4. Oddly, there are no such functions
+ 1988) incorporated 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 versions. This implementation (as well as the X/Open
+ o Most implementations simply dump the binary WINDOW structure to the
+ file. These include SVr4 curses, NetBSD and PDCurses, as well as
+ older ncurses versions. 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
+ 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. However, reading from a
+ 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. However, reading from a
file written using mixed schemes may not be successful.
-
- 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 conditions. This implementation checks for
- three cases:
+
+ X/Open Curses, Issue 4 describes these functions. It states that
+ unctrl and wunctrl will return a null pointer if unsuccessful, but does
+ not define any error conditions. This implementation checks for three
+ cases:
- o the parameter is a 7-bit US-ASCII code. This is the case that
+ 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 control code. If
- use_legacy_coding(3x) has been called with a 2 parameter, unctrl
- returns the parameter, i.e., a one-character string with the param-
- eter as the first character. Otherwise, it returns "~@", "~A",
- etc., analogous to "^@", "^A", C0 controls.
+ use_legacy_coding(3x) 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
@@ -321,43 +354,44 @@
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 conven-
- tions. 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(3x) function allows the caller to change the output
- of unctrl.
-
- Likewise, the meta(3x) 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_cod-
- ing(3x) and meta(3x) 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 initializ-
- ing curses), this implementation returns strings "M-^@", "M-^A", etc.
-
- X/Open Curses documents unctrl as declared in <unctrl.h>, which ncurses
- does. However, ncurses' <curses.h> includes <unctrl.h>, matching the
+ 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 printable.
+ This implementation uses 8 bits but does not modify the string to
+ reflect locale. The use_legacy_coding(3x) function allows the caller
+ to change the output of unctrl.
+
+ Likewise, the meta(3x) 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(3x) and meta(3x) 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.
+
+ X/Open Curses documents unctrl as declared in <unctrl.h>, which ncurses
+ does. However, ncurses' <curses.h> includes <unctrl.h>, matching the
behavior of SVr4 curses. Other implementations may not do that.
-
+ If ncurses is configured to provide the sp-functions extension, the
state of use_env and use_tioctl may be updated before creating each
screen rather than once only (curs_sp_funcs(3x)). This feature of
- use_env is not provided by other implementation of curses.
+ use_env is not provided by other implementations of curses.