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30 * @Id: curs_util.3x,v 1.37 2013/07/20 19:43:45 tom Exp @
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45 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG> <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
51 <H2><a name="h2-NAME">NAME</a></H2><PRE>
52 <STRONG>delay_output</STRONG>, <STRONG>filter</STRONG>, <STRONG>flushinp</STRONG>, <STRONG>getwin</STRONG>, <STRONG>key_name</STRONG>, <STRONG>keyname</STRONG>,
53 <STRONG>nofilter</STRONG>, <STRONG>putwin</STRONG>, <STRONG>unctrl</STRONG>, <STRONG>use_env</STRONG>, <STRONG>use_tioctl</STRONG>, <STRONG>wunctrl</STRONG> -
54 miscellaneous <STRONG>curses</STRONG> utility routines
58 <H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
59 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
61 <STRONG>char</STRONG> <STRONG>*unctrl(chtype</STRONG> <STRONG>c);</STRONG>
62 <STRONG>wchar_t</STRONG> <STRONG>*wunctrl(cchar_t</STRONG> <STRONG>*c);</STRONG>
63 <STRONG>char</STRONG> <STRONG>*keyname(int</STRONG> <STRONG>c);</STRONG>
64 <STRONG>char</STRONG> <STRONG>*key_name(wchar_t</STRONG> <STRONG>w);</STRONG>
65 <STRONG>void</STRONG> <STRONG>filter(void);</STRONG>
66 <STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
67 <STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <STRONG>f);</STRONG>
68 <STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <STRONG>f);</STRONG>
69 <STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>FILE</STRONG> <STRONG>*filep);</STRONG>
70 <STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*filep);</STRONG>
71 <STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <STRONG>ms);</STRONG>
72 <STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
76 <H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
77 The <STRONG>unctrl</STRONG> routine returns a character string which is a
78 printable representation of the character <EM>c</EM>, ignoring at-
79 tributes. Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> no-
80 tation. Printing characters are displayed as is. The
81 corresponding <STRONG>wunctrl</STRONG> returns a printable representation
84 The <STRONG>keyname</STRONG> routine returns a character string correspond-
85 ing to the key <EM>c</EM>:
87 <STRONG>o</STRONG> Printable characters are displayed as themselves,
88 e.g., a one-character string containing the key.
90 <STRONG>o</STRONG> Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> nota-
93 <STRONG>o</STRONG> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
95 <STRONG>o</STRONG> Values above 128 are either meta characters (if the
96 screen has not been initialized, or if <STRONG>meta</STRONG> has
97 been called with a TRUE parameter), shown in the
98 <STRONG>M-</STRONG><EM>X</EM> notation, or are displayed as themselves. In
99 the latter case, the values may not be printable;
100 this follows the X/Open specification.
102 <STRONG>o</STRONG> Values above 256 may be the names of the names of
105 <STRONG>o</STRONG> Otherwise (if there is no corresponding name) the
106 function returns null, to denote an error. X/Open
107 also lists an "UNKNOWN KEY" return value, which
108 some implementations return rather than null.
110 The corresponding <STRONG>key_name</STRONG> returns a character string cor-
111 responding to the wide-character value <EM>w</EM>. The two func-
112 tions do not return the same set of strings; the latter
113 returns null where the former would display a meta charac-
116 The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG>
117 or <STRONG>newterm</STRONG> are called. The effect is that, during those
118 calls, <STRONG>LINES</STRONG> is set to 1; the capabilities <STRONG>clear</STRONG>, <STRONG>cup</STRONG>,
119 <STRONG>cud</STRONG>, <STRONG>cud1</STRONG>, <STRONG>cuu1</STRONG>, <STRONG>cuu</STRONG>, <STRONG>vpa</STRONG> are disabled; and the <STRONG>home</STRONG>
120 string is set to the value of <STRONG>cr</STRONG>.
122 The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding
123 <STRONG>filter</STRONG> call. That allows the caller to initialize a
124 screen on a different device, using a different value of
125 <STRONG>$TERM</STRONG>. The limitation arises because the <STRONG>filter</STRONG> routine
126 modifies the in-memory copy of the terminal information.
128 The <STRONG>use_env</STRONG> routine, if used, should be called before
129 <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG> are called (because those compute the
130 screen size). It modifies the way <STRONG>ncurses</STRONG> treats environ-
131 ment variables when determining the screen size.
133 <STRONG>o</STRONG> Normally ncurses looks first at the terminal database
136 If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it
137 stops here unless If <STRONG>use_tioctl</STRONG> was also called with
138 <STRONG>TRUE</STRONG> for parameter.
140 <STRONG>o</STRONG> Then it asks for the screen size via operating system
141 calls. If successful, it overrides the values from
142 the terminal database.
144 <STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parame-
145 ter), ncurses examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environ-
146 ment variables, using a value in those to override the
147 results from the operating system or terminal data-
150 Ncurses also updates the screen size in response to
151 SIGWINCH, unless overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG>
152 environment variables,
154 The <STRONG>use_tioctl</STRONG> routine, if used, should be called before
155 <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG> are called (because those compute the
156 screen size). After <STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an
157 argument, ncurses modifies the last step in its computa-
158 tion of screen size as follows:
160 <STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables
161 are set to a number greater than zero.
163 <STRONG>o</STRONG> for each, ncurses updates the corresponding environ-
164 ment variable with the value that it has obtained via
165 operating system call or from the terminal database.
167 <STRONG>o</STRONG> ncurses re-fetches the value of the environment vari-
168 ables so that it is still the environment variables
169 which set the screen size.
171 The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as summarized
174 <EM>use</EM><STRONG>_</STRONG><EM>env</EM> <EM>use</EM><STRONG>_</STRONG><EM>tioctl</EM> <EM>Summary</EM>
175 ----------------------------------------------------------------
176 TRUE FALSE This is the default behavior. ncurses
177 uses operating system calls unless over-
178 ridden by $LINES or $COLUMNS environment
180 TRUE TRUE ncurses updates $LINES and $COLUMNS
181 based on operating system calls.
183 FALSE TRUE ncurses ignores $LINES and $COLUMNS, us-
184 es operating system calls to obtain
186 FALSE FALSE ncurses relies on the terminal database
189 The <STRONG>putwin</STRONG> routine writes all data associated with window
190 <EM>win</EM> into the file to which <EM>filep</EM> points. This information
191 can be later retrieved using the <STRONG>getwin</STRONG> function.
193 The <STRONG>getwin</STRONG> routine reads window related data stored in the
194 file by <STRONG>putwin</STRONG>. The routine then creates and initializes
195 a new window using that data. It returns a pointer to the
198 The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause
199 in output. This routine should not be used extensively
200 because padding characters are used rather than a CPU
201 pause. If no padding character is specified, this uses
202 <STRONG>napms</STRONG> to perform the delay.
204 The <STRONG>flushinp</STRONG> routine throws away any typeahead that has
205 been typed by the user and has not yet been read by the
210 <H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
211 Except for <STRONG>flushinp</STRONG>, routines that return an integer re-
212 turn <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4 specifies only "an in-
213 teger value other than <STRONG>ERR</STRONG>") upon successful completion.
215 Routines that return pointers return <STRONG>NULL</STRONG> on error.
217 X/Open does not define any error conditions. In this im-
220 <STRONG>flushinp</STRONG>
221 returns an error if the terminal was not initial-
224 <STRONG>meta</STRONG> returns an error if the terminal was not initial-
227 <STRONG>putwin</STRONG>
228 returns an error if the associated <STRONG>fwrite</STRONG> calls
233 <H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
234 The XSI Curses standard, Issue 4 describes these func-
235 tions. It states that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a
236 null pointer if unsuccessful, but does not define any er-
237 ror conditions. This implementation checks for three cas-
240 <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is
241 the case that X/Open Curses documented.
243 <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1
244 control code. If <STRONG>use_legacy_coding</STRONG> has been called
245 with a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG> returns the parameter,
246 i.e., a one-character string with the parameter as
247 the first character. Otherwise, it returns "~@",
248 "~A", etc., analogous to "^@", "^A", C0 controls.
250 X/Open Curses does not document whether <STRONG>unctrl</STRONG> can
251 be called before initializing curses. This imple-
252 mentation permits that, and returns the "~@", etc.,
255 <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unc-</STRONG>
256 <STRONG>trl</STRONG> returns a null pointer.
258 The SVr4 documentation describes the action of <STRONG>filter</STRONG> only
259 in the vaguest terms. The description here is adapted
260 from the XSI Curses standard (which erroneously fails to
261 describe the disabling of <STRONG>cuu</STRONG>).
263 The strings returned by <STRONG>unctrl</STRONG> in this implementation are
264 determined at compile time, showing C1 controls from the
265 upper-128 codes with a `~' prefix rather than `^'. Other
266 implementations have different conventions. For example,
267 they may show both sets of control characters with `^',
268 and strip the parameter to 7 bits. Or they may ignore C1
269 controls and treat all of the upper-128 codes as print-
270 able. This implementation uses 8 bits but does not modify
271 the string to reflect locale. The <STRONG>use_legacy_coding</STRONG> func-
272 tion allows the caller to change the output of <STRONG>unctrl</STRONG>.
274 Likewise, the <STRONG>meta</STRONG> function allows the caller to change
275 the output of <STRONG>keyname</STRONG>, i.e., it determines whether to use
276 the `M-' prefix for "meta" keys (codes in the range 128 to
277 255). Both <STRONG>use_legacy_coding</STRONG> and <STRONG>meta</STRONG> succeed only after
278 curses is initialized. X/Open Curses does not document
279 the treatment of codes 128 to 159. When treating them as
280 "meta" keys (or if <STRONG>keyname</STRONG> is called before initializing
281 curses), this implementation returns strings "M-^@",
284 The <STRONG>keyname</STRONG> function may return the names of user-defined
285 string capabilities which are defined in the terminfo en-
286 try via the <STRONG>-x</STRONG> option of <STRONG>tic</STRONG>. This implementation auto-
287 matically assigns at run-time keycodes to user-defined
288 strings which begin with "k". The keycodes start at
289 KEY_MAX, but are not guaranteed to be the same value for
290 different runs because user-defined codes are merged from
291 all terminal descriptions which have been loaded. The
292 <STRONG>use_extended_names</STRONG> function controls whether this data is
293 loaded when the terminal description is read by the li-
296 The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to
297 ncurses. They were not supported on Version 7, BSD or
298 System V implementations. It is recommended that any code
299 depending on ncurses extensions be conditioned using
304 <H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
305 <STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>, <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG>curs_ker-</STRONG>
306 <STRONG><A HREF="curs_kernel.3x.html">nel(3x)</A></STRONG>, <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>lega-</STRONG>
307 <STRONG><A HREF="legacy_coding.3x.html">cy_coding(3x)</A></STRONG>.
311 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
315 <li><a href="#h2-NAME">NAME</a></li>
316 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
317 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
318 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
319 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
320 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>