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31 * @Id: curs_util.3x,v 1.65 2022/02/12 20:06:41 tom Exp @
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43 <H1 class="no-header">curs_util 3x</H1>
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>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 <STRONG>delay_output</STRONG>, <STRONG>filter</STRONG>, <STRONG>flushinp</STRONG>, <STRONG>getwin</STRONG>, <STRONG>key_name</STRONG>, <STRONG>keyname</STRONG>, <STRONG>nofilter</STRONG>,
52 <STRONG>putwin</STRONG>, <STRONG>unctrl</STRONG>, <STRONG>use_env</STRONG>, <STRONG>use_tioctl</STRONG>, <STRONG>wunctrl</STRONG> - miscellaneous <STRONG>curses</STRONG>
56 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
57 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
59 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*unctrl(chtype</STRONG> <EM>c</EM><STRONG>);</STRONG>
60 <STRONG>wchar_t</STRONG> <STRONG>*wunctrl(cchar_t</STRONG> <STRONG>*</STRONG><EM>c</EM><STRONG>);</STRONG>
62 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*keyname(int</STRONG> <EM>c</EM><STRONG>);</STRONG>
63 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*key_name(wchar_t</STRONG> <EM>w</EM><STRONG>);</STRONG>
65 <STRONG>void</STRONG> <STRONG>filter(void);</STRONG>
66 <STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
68 <STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <EM>f</EM><STRONG>);</STRONG>
69 <STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <EM>f</EM><STRONG>);</STRONG>
71 <STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>FILE</STRONG> <STRONG>*</STRONG><EM>filep</EM><STRONG>);</STRONG>
72 <STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*</STRONG><EM>filep</EM><STRONG>);</STRONG>
74 <STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <EM>ms</EM><STRONG>);</STRONG>
75 <STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
78 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
80 </PRE><H3><a name="h3-unctrl">unctrl</a></H3><PRE>
81 The <STRONG>unctrl</STRONG> routine returns a character string which is a printable rep-
82 resentation of the character <EM>c</EM>, ignoring attributes. Control charac-
83 ters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation. Printing characters are dis-
84 played as is. The corresponding <STRONG>wunctrl</STRONG> returns a printable represen-
85 tation of a wide character.
88 </PRE><H3><a name="h3-keyname_key_name">keyname/key_name</a></H3><PRE>
89 The <STRONG>keyname</STRONG> routine returns a character string corresponding to the key
92 <STRONG>o</STRONG> Printable characters are displayed as themselves, e.g., a one-char-
93 acter string containing the key.
95 <STRONG>o</STRONG> Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation.
97 <STRONG>o</STRONG> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
99 <STRONG>o</STRONG> Values above 128 are either meta characters (if the screen has not
100 been initialized, or if <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> has been called with a <STRONG>TRUE</STRONG> param-
101 eter), shown in the <STRONG>M-</STRONG><EM>X</EM> notation, or are displayed as themselves.
102 In the latter case, the values may not be printable; this follows
103 the X/Open specification.
105 <STRONG>o</STRONG> Values above 256 may be the names of the names of function keys.
107 <STRONG>o</STRONG> Otherwise (if there is no corresponding name) the function returns
108 null, to denote an error. X/Open also lists an "UNKNOWN KEY" re-
109 turn value, which some implementations return rather than null.
111 The corresponding <STRONG>key_name</STRONG> returns a character string corresponding to
112 the wide-character value <EM>w</EM>. The two functions do not return the same
113 set of strings; the latter returns null where the former would display
117 </PRE><H3><a name="h3-filter_nofilter">filter/nofilter</a></H3><PRE>
118 The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>
119 are called. Calling <STRONG>filter</STRONG> causes these changes in initialization:
121 <STRONG>o</STRONG> <STRONG>LINES</STRONG> is set to 1;
123 <STRONG>o</STRONG> the capabilities <STRONG>clear</STRONG>, <STRONG>cud1</STRONG>, <STRONG>cud</STRONG>, <STRONG>cup</STRONG>, <STRONG>cuu1</STRONG>, <STRONG>cuu</STRONG>, <STRONG>vpa</STRONG> are dis-
126 <STRONG>o</STRONG> the capability <STRONG>ed</STRONG> is disabled if <STRONG>bce</STRONG> is set;
128 <STRONG>o</STRONG> and the <STRONG>home</STRONG> string is set to the value of <STRONG>cr</STRONG>.
130 The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding <STRONG>filter</STRONG> call.
131 That allows the caller to initialize a screen on a different device,
132 using a different value of <STRONG>$TERM</STRONG>. The limitation arises because the
133 <STRONG>filter</STRONG> routine modifies the in-memory copy of the terminal information.
136 </PRE><H3><a name="h3-use_env">use_env</a></H3><PRE>
137 The <STRONG>use_env</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
138 <STRONG>newterm</STRONG> are called (because those compute the screen size). It modi-
139 fies the way <STRONG>ncurses</STRONG> treats environment variables when determining the
142 <STRONG>o</STRONG> Normally <STRONG>ncurses</STRONG> looks first at the terminal database for the
145 If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it stops here un-
146 less <STRONG>use_tioctl</STRONG> was also called with <STRONG>TRUE</STRONG> for parameter.
148 <STRONG>o</STRONG> Then it asks for the screen size via operating system calls. If
149 successful, it overrides the values from the terminal database.
151 <STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parameter), <STRONG>ncurses</STRONG>
152 examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables, using a value
153 in those to override the results from the operating system or ter-
156 <STRONG>Ncurses</STRONG> also updates the screen size in response to <STRONG>SIGWINCH</STRONG>, un-
157 less overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables,
160 </PRE><H3><a name="h3-use_tioctl">use_tioctl</a></H3><PRE>
161 The <STRONG>use_tioctl</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
162 <STRONG>newterm</STRONG> are called (because those compute the screen size). After
163 <STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an argument, <STRONG>ncurses</STRONG> modifies the
164 last step in its computation of screen size as follows:
166 <STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables are set to a
167 number greater than zero.
169 <STRONG>o</STRONG> for each, <STRONG>ncurses</STRONG> updates the corresponding environment variable
170 with the value that it has obtained via operating system call or
171 from the terminal database.
173 <STRONG>o</STRONG> <STRONG>ncurses</STRONG> re-fetches the value of the environment variables so that
174 it is still the environment variables which set the screen size.
176 The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as summarized here:
178 <STRONG>use_env</STRONG> <STRONG>use_tioctl</STRONG> <STRONG>Summary</STRONG>
179 ----------------------------------------------------------------
180 TRUE FALSE This is the default behavior. <STRONG>ncurses</STRONG>
181 uses operating system calls unless over-
182 ridden by $LINES or $COLUMNS environment
185 TRUE TRUE <STRONG>ncurses</STRONG> updates $LINES and $COLUMNS
186 based on operating system calls.
187 FALSE TRUE <STRONG>ncurses</STRONG> ignores $LINES and $COLUMNS, us-
188 es operating system calls to obtain
190 FALSE FALSE <STRONG>ncurses</STRONG> relies on the terminal database
194 </PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
195 The <STRONG>putwin</STRONG> routine writes all data associated with window (or pad) <EM>win</EM>
196 into the file to which <EM>filep</EM> points. This information can be later re-
197 trieved using the <STRONG>getwin</STRONG> function.
199 The <STRONG>getwin</STRONG> routine reads window related data stored in the file by
200 <STRONG>putwin</STRONG>. The routine then creates and initializes a new window using
201 that data. It returns a pointer to the new window. There are a few
204 <STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure, and its associ-
205 ated character cells. The format differs between the wide-charac-
206 ter (<STRONG>ncursesw</STRONG>) and non-wide (<STRONG>ncurses</STRONG>) libraries. You can transfer
207 data between the two, however.
209 <STRONG>o</STRONG> the retrieved window is always created as a top-level window (or
210 pad), rather than a subwindow.
212 <STRONG>o</STRONG> the window's character cells contain the color pair <EM>value</EM>, but not
213 the actual color <EM>numbers</EM>. If cells in the retrieved window use
214 color pairs which have not been created in the application using
215 <STRONG>init_pair</STRONG>, they will not be colored when the window is refreshed.
218 </PRE><H3><a name="h3-delay_output">delay_output</a></H3><PRE>
219 The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause in output.
220 This routine should not be used extensively because padding characters
221 are used rather than a CPU pause. If no padding character is speci-
222 fied, this uses <STRONG>napms</STRONG> to perform the delay.
225 </PRE><H3><a name="h3-flushinp">flushinp</a></H3><PRE>
226 The <STRONG>flushinp</STRONG> routine throws away any typeahead that has been typed by
227 the user and has not yet been read by the program.
230 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
231 Except for <STRONG>flushinp</STRONG>, routines that return an integer return <STRONG>ERR</STRONG> upon
232 failure and <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>")
233 upon successful completion.
235 Routines that return pointers return <STRONG>NULL</STRONG> on error.
237 X/Open does not define any error conditions. In this implementation
239 <STRONG>flushinp</STRONG>
240 returns an error if the terminal was not initialized.
242 <STRONG>putwin</STRONG>
243 returns an error if the associated <STRONG>fwrite</STRONG> calls return an er-
247 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
249 </PRE><H3><a name="h3-filter">filter</a></H3><PRE>
250 The SVr4 documentation describes the action of <STRONG>filter</STRONG> only in the
251 vaguest terms. The description here is adapted from the XSI Curses
252 standard (which erroneously fails to describe the disabling of <STRONG>cuu</STRONG>).
255 </PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
256 The <STRONG>keyname</STRONG> function may return the names of user-defined string capa-
257 bilities which are defined in the terminfo entry via the <STRONG>-x</STRONG> option of
258 <STRONG>tic</STRONG>. This implementation automatically assigns at run-time keycodes to
259 user-defined strings which begin with "k". The keycodes start at
260 KEY_MAX, but are not guaranteed to be the same value for different runs
261 because user-defined codes are merged from all terminal descriptions
262 which have been loaded. The <STRONG><A HREF="curs_extend.3x.html">use_extended_names(3x)</A></STRONG> function controls
263 whether this data is loaded when the terminal description is read by
267 </PRE><H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
268 The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to <STRONG>ncurses</STRONG>. They
269 were not supported on Version 7, BSD or System V implementations. It
270 is recommended that any code depending on <STRONG>ncurses</STRONG> extensions be condi-
271 tioned using NCURSES_VERSION.
274 </PRE><H3><a name="h3-putwin_getwin-file-format">putwin/getwin file-format</a></H3><PRE>
275 The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with portability:
277 <STRONG>o</STRONG> The files written and read by these functions use an implementa-
278 tion-specific format. Although the format is an obvious target for
279 standardization, it has been overlooked.
281 Interestingly enough, according to the copyright dates in Solaris
282 source, the functions (along with <STRONG>scr_init</STRONG>, etc.) originated with
283 the University of California, Berkeley (in 1982) and were later (in
284 1988) incorporated into SVr4. Oddly, there are no such functions
285 in the 4.3BSD curses sources.
287 <STRONG>o</STRONG> Most implementations simply dump the binary <STRONG>WINDOW</STRONG> structure to the
288 file. These include SVr4 curses, NetBSD and PDCurses, as well as
289 older <STRONG>ncurses</STRONG> versions. This implementation (as well as the X/Open
290 variant of Solaris curses, dated 1995) uses textual dumps.
292 The implementations which use binary dumps use block-I/O (the
293 <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use textual dumps use
294 buffered-I/O. A few applications may happen to write extra data in
295 the file using these functions. Doing that can run into problems
296 mixing block- and buffered-I/O. This implementation reduces the
297 problem on writes by flushing the output. However, reading from a
298 file written using mixed schemes may not be successful.
301 </PRE><H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
302 The XSI Curses standard, Issue 4 describes these functions. It states
303 that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but
304 does not define any error conditions. This implementation checks for
307 <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
308 X/Open Curses documented.
310 <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
311 <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> has been called with a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG>
312 returns the parameter, i.e., a one-character string with the param-
313 eter as the first character. Otherwise, it returns "~@", "~A",
314 etc., analogous to "^@", "^A", C0 controls.
316 X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
317 initializing curses. This implementation permits that, and returns
318 the "~@", etc., values in that case.
320 <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
323 The strings returned by <STRONG>unctrl</STRONG> in this implementation are determined at
324 compile time, showing C1 controls from the upper-128 codes with a "~"
325 prefix rather than "^". Other implementations have different conven-
326 tions. For example, they may show both sets of control characters with
327 "^", and strip the parameter to 7 bits. Or they may ignore C1 controls
328 and treat all of the upper-128 codes as printable. This implementation
329 uses 8 bits but does not modify the string to reflect locale. The
330 <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> function allows the caller to change the output
331 of <STRONG>unctrl</STRONG>.
333 Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
334 of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
335 "meta" keys (codes in the range 128 to 255). Both <STRONG>use_legacy_cod-</STRONG>
336 <STRONG><A HREF="use_legacy_coding.3x.html">ing(3x)</A></STRONG> and <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> succeed only after curses is initialized. X/Open
337 Curses does not document the treatment of codes 128 to 159. When
338 treating them as "meta" keys (or if <STRONG>keyname</STRONG> is called before initializ-
339 ing curses), this implementation returns strings "M-^@", "M-^A", etc.
341 X/Open Curses documents <STRONG>unctrl</STRONG> as declared in <STRONG><unctrl.h></STRONG>, which <STRONG>ncurses</STRONG>
342 does. However, <STRONG>ncurses</STRONG>' <STRONG><curses.h></STRONG> includes <STRONG><unctrl.h></STRONG>, matching the
343 behavior of SVr4 curses. Other implementations may not do that.
346 </PRE><H3><a name="h3-use_env_use_tioctl">use_env/use_tioctl</a></H3><PRE>
347 If <STRONG>ncurses</STRONG> is configured to provide the sp-functions extension, the
348 state of <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> may be updated before creating each
349 <EM>screen</EM> rather than once only (<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>). This feature of
350 <STRONG>use_env</STRONG> is not provided by other implementation of curses.
353 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
354 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>, <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>,
355 <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>, <STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>legacy_cod-</STRONG>
356 <STRONG><A HREF="legacy_coding.3x.html">ing(3x)</A></STRONG>.
360 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
364 <li><a href="#h2-NAME">NAME</a></li>
365 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
366 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
368 <li><a href="#h3-unctrl">unctrl</a></li>
369 <li><a href="#h3-keyname_key_name">keyname/key_name</a></li>
370 <li><a href="#h3-filter_nofilter">filter/nofilter</a></li>
371 <li><a href="#h3-use_env">use_env</a></li>
372 <li><a href="#h3-use_tioctl">use_tioctl</a></li>
373 <li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
374 <li><a href="#h3-delay_output">delay_output</a></li>
375 <li><a href="#h3-flushinp">flushinp</a></li>
378 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
379 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
381 <li><a href="#h3-filter">filter</a></li>
382 <li><a href="#h3-keyname">keyname</a></li>
383 <li><a href="#h3-nofilter_use_tioctl">nofilter/use_tioctl</a></li>
384 <li><a href="#h3-putwin_getwin-file-format">putwin/getwin file-format</a></li>
385 <li><a href="#h3-unctrl_wunctrl">unctrl/wunctrl</a></li>
386 <li><a href="#h3-use_env_use_tioctl">use_env/use_tioctl</a></li>
389 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>