1curs_util(3X) curs_util(3X)
2
6 delay_output, filter, flushinp, getwin, key_name, keyname, nofilter,
7 putwin, unctrl, use_env, wunctrl - miscellaneous curses utility
8 routines
9
11 #include <curses.h>
12 char *unctrl(chtype c);
14 wchar_t *wunctrl(cchar_t *c);
15 char *keyname(int c);
16 char *key_name(wchar_t w);
17 void filter(void);
18 void nofilter(void);
19 void use_env(bool f);
20 int putwin(WINDOW *win, FILE *filep);
21 WINDOW *getwin(FILE *filep);
22 int delay_output(int ms);
23 int flushinp(void);
24
26 The unctrl routine returns a character string which is a printable rep‐
27 resentation of the character c, ignoring attributes. Control charac‐
28 ters are displayed in the ^X notation. Printing characters are dis‐
29 played as is. The corresponding wunctrl returns a printable represen‐
30 tation of a wide-character.
31 The keyname routine returns a character string corresponding to the key
33 c:
34 - Printable characters are displayed as themselves, e.g., a one-
36 character string containing the key.
37 - Control characters are displayed in the ^X notation.
39 - DEL (character 127) is displayed as ^?.
41 - Values above 128 are either meta characters (if the screen has
43 not been initialized, or if meta has been called with a TRUE pa‐
44 rameter), shown in the M-X notation, or are displayed as them‐
45 selves. In the latter case, the values may not be printable;
46 this follows the X/Open specification.
47 - Values above 256 may be the names of the names of function keys.
49 - Otherwise (if there is no corresponding name) the function re‐
51 turns null, to denote an error. X/Open also lists an "UNKNOWN
52 KEY" return value, which some implementations return rather than
53 null.
54 The corresponding key_name returns a character string corresponding to
56 the wide-character value w. The two functions do not return the same
57 set of strings; the latter returns null where the former would display
58 a meta character.
59 The filter routine, if used, must be called before initscr or newterm
61 are called. The effect is that, during those calls, LINES is set to 1;
62 the capabilities clear, cup, cud, cud1, cuu1, cuu, vpa are disabled;
63 and the home string is set to the value of cr.
64 The nofilter routine cancels the effect of a preceding filter call.
66 That allows the caller to initialize a screen on a different device,
67 using a different value of $TERM. The limitation arises because the
68 filter routine modifies the in-memory copy of the terminal information.
69 The use_env routine, if used, is called before initscr or newterm are
71 called. When called with FALSE as an argument, the values of lines and
72 columns specified in the terminfo database will be used, even if envi‐
73 ronment variables LINES and COLUMNS (used by default) are set, or if
74 curses is running in a window (in which case default behavior would be
75 to use the window size if LINES and COLUMNS are not set). Note that
76 setting LINES or COLUMNS overrides the corresponding size which may be
77 obtained from the operating system.
78 The putwin routine writes all data associated with window win into the
80 file to which filep points. This information can be later retrieved
81 using the getwin function.
82 The getwin routine reads window related data stored in the file by
84 putwin. The routine then creates and initializes a new window using
85 that data. It returns a pointer to the new window.
86 The delay_output routine inserts an ms millisecond pause in output.
88 This routine should not be used extensively because padding characters
89 are used rather than a CPU pause. If no padding character is speci‐
90 fied, this uses napms to perform the delay.
91 The flushinp routine throws away any typeahead that has been typed by
93 the user and has not yet been read by the program.
94
96 Except for flushinp, routines that return an integer return ERR upon
97 failure and OK (SVr4 specifies only "an integer value other than ERR")
98 upon successful completion.
99 Routines that return pointers return NULL on error.
101 X/Open does not define any error conditions. In this implementation
103 flushinp
105 returns an error if the terminal was not initialized.
106 meta returns an error if the terminal was not initialized.
108 putwin
110 returns an error if the associated fwrite calls return an er‐
111 ror.
112
114 The XSI Curses standard, Issue 4 describes these functions. It states
115 that unctrl and wunctrl will return a null pointer if unsuccessful, but
116 does not define any error conditions. This implementation checks for
117 three cases:
118 - the parameter is a 7-bit US-ASCII code. This is the case
120 that X/Open Curses documented.
121 - the parameter is in the range 128-159, i.e., a C1 control
123 code. If use_legacy_coding has been called with a 2 param‐
124 eter, unctrl returns the parameter, i.e., a one-character
125 string with the parameter as the first character. Other‐
126 wise, it returns ``~@'', ``~A'', etc., analogous to ``^@'',
127 ``^A'', C0 controls.
128 X/Open Curses does not document whether unctrl can be
130 called before initializing curses. This implementation
131 permits that, and returns the ``~@'', etc., values in that
132 case.
133 - parameter values outside the 0 to 255 range. unctrl re‐
135 turns a null pointer.
136 The SVr4 documentation describes the action of filter only in the
138 vaguest terms. The description here is adapted from the XSI Curses
139 standard (which erroneously fails to describe the disabling of cuu).
140 The strings returned by unctrl in this implementation are determined at
142 compile time, showing C1 controls from the upper-128 codes with a `~'
143 prefix rather than `^'. Other implementations have different conven‐
144 tions. For example, they may show both sets of control characters with
145 `^', and strip the parameter to 7 bits. Or they may ignore C1 controls
146 and treat all of the upper-128 codes as printable. This implementation
147 uses 8 bits but does not modify the string to reflect locale. The
148 use_legacy_coding function allows the caller to change the output of
149 unctrl.
150 Likewise, the meta function allows the caller to change the output of
152 keyname, i.e., it determines whether to use the `M-' prefix for
153 ``meta'' keys (codes in the range 128 to 255). Both use_legacy_coding
154 and meta succeed only after curses is initialized. X/Open Curses does
155 not document the treatment of codes 128 to 159. When treating them as
156 ``meta'' keys (or if keyname is called before initializing curses),
157 this implementation returns strings ``M-^@'', ``M-^A'', etc.
158 The keyname function may return the names of user-defined string capa‐
160 bilities which are defined in the terminfo entry via the -x option of
161 tic. This implementation automatically assigns at run-time keycodes to
162 user-defined strings which begin with "k". The keycodes start at
163 KEY_MAX, but are not guaranteed to be the same value for different runs
164 because user-defined codes are merged from all terminal descriptions
165 which have been loaded. The use_extended_names function controls
166 whether this data is loaded when the terminal description is read by
167 the library.
168 The nofilter routine is specific to ncurses. It was not supported on
170 Version 7, BSD or System V implementations. It is recommended that any
171 code depending on ncurses extensions be conditioned using NCURSES_VER‐
172 SION.
173
175 legacy_coding(3X), curses(3X), curs_initscr(3X), curs_kernel(3X),
176 curs_scr_dump(3X), legacy_coding(3X).
177 curs_util(3X)