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31 * @Id: curs_util.3x,v 1.57 2020/02/02 23:34:34 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> <STRONG>c);</STRONG>
60 <STRONG>wchar_t</STRONG> <STRONG>*wunctrl(cchar_t</STRONG> <STRONG>*c);</STRONG>
61 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*keyname(int</STRONG> <STRONG>c);</STRONG>
62 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*key_name(wchar_t</STRONG> <STRONG>w);</STRONG>
63 <STRONG>void</STRONG> <STRONG>filter(void);</STRONG>
64 <STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
65 <STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <STRONG>f);</STRONG>
66 <STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <STRONG>f);</STRONG>
67 <STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>FILE</STRONG> <STRONG>*filep);</STRONG>
68 <STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*filep);</STRONG>
69 <STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <STRONG>ms);</STRONG>
70 <STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
73 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
75 </PRE><H3><a name="h3-unctrl">unctrl</a></H3><PRE>
76 The <STRONG>unctrl</STRONG> routine returns a character string which is a printable rep-
77 resentation of the character <EM>c</EM>, ignoring attributes. Control charac-
78 ters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation. Printing characters are dis-
79 played as is. The corresponding <STRONG>wunctrl</STRONG> returns a printable represen-
80 tation of a wide character.
83 </PRE><H3><a name="h3-keyname_key_name">keyname/key_name</a></H3><PRE>
84 The <STRONG>keyname</STRONG> routine returns a character string corresponding to the key
87 <STRONG>o</STRONG> Printable characters are displayed as themselves, e.g., a one-char-
88 acter string containing the key.
90 <STRONG>o</STRONG> Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation.
92 <STRONG>o</STRONG> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
94 <STRONG>o</STRONG> Values above 128 are either meta characters (if the screen has not
95 been initialized, or if <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> has been called with a <STRONG>TRUE</STRONG> param-
96 eter), shown in the <STRONG>M-</STRONG><EM>X</EM> notation, or are displayed as themselves.
97 In the latter case, the values may not be printable; this follows
98 the X/Open specification.
100 <STRONG>o</STRONG> Values above 256 may be the names of the names of function keys.
102 <STRONG>o</STRONG> Otherwise (if there is no corresponding name) the function returns
103 null, to denote an error. X/Open also lists an "UNKNOWN KEY" re-
104 turn value, which some implementations return rather than null.
106 The corresponding <STRONG>key_name</STRONG> returns a character string corresponding to
107 the wide-character value <EM>w</EM>. The two functions do not return the same
108 set of strings; the latter returns null where the former would display
112 </PRE><H3><a name="h3-filter_nofilter">filter/nofilter</a></H3><PRE>
113 The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>
114 are called. Calling <STRONG>filter</STRONG> causes these changes in initialization:
116 <STRONG>o</STRONG> <STRONG>LINES</STRONG> is set to 1;
118 <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-
121 <STRONG>o</STRONG> the capability <STRONG>ed</STRONG> is disabled if <STRONG>bce</STRONG> is set;
123 <STRONG>o</STRONG> and the <STRONG>home</STRONG> string is set to the value of <STRONG>cr</STRONG>.
125 The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding <STRONG>filter</STRONG> call.
126 That allows the caller to initialize a screen on a different device,
127 using a different value of <STRONG>$TERM</STRONG>. The limitation arises because the
128 <STRONG>filter</STRONG> routine modifies the in-memory copy of the terminal information.
131 </PRE><H3><a name="h3-use_env">use_env</a></H3><PRE>
132 The <STRONG>use_env</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
133 <STRONG>newterm</STRONG> are called (because those compute the screen size). It modi-
134 fies the way <STRONG>ncurses</STRONG> treats environment variables when determining the
137 <STRONG>o</STRONG> Normally <STRONG>ncurses</STRONG> looks first at the terminal database for the
140 If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it stops here un-
141 less <STRONG>use_tioctl</STRONG> was also called with <STRONG>TRUE</STRONG> for parameter.
143 <STRONG>o</STRONG> Then it asks for the screen size via operating system calls. If
144 successful, it overrides the values from the terminal database.
146 <STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parameter), <STRONG>ncurses</STRONG>
147 examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables, using a value
148 in those to override the results from the operating system or ter-
151 <STRONG>Ncurses</STRONG> also updates the screen size in response to <STRONG>SIGWINCH</STRONG>, un-
152 less overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables,
155 </PRE><H3><a name="h3-use_tioctl">use_tioctl</a></H3><PRE>
156 The <STRONG>use_tioctl</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
157 <STRONG>newterm</STRONG> are called (because those compute the screen size). After
158 <STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an argument, <STRONG>ncurses</STRONG> modifies the
159 last step in its computation of screen size as follows:
161 <STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables are set to a
162 number greater than zero.
164 <STRONG>o</STRONG> for each, <STRONG>ncurses</STRONG> updates the corresponding environment variable
165 with the value that it has obtained via operating system call or
166 from the terminal database.
168 <STRONG>o</STRONG> <STRONG>ncurses</STRONG> re-fetches the value of the environment variables so that
169 it is still the environment variables which set the screen size.
171 The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as summarized here:
173 <EM>use</EM><STRONG>_</STRONG><EM>env</EM> <EM>use</EM><STRONG>_</STRONG><EM>tioctl</EM> <EM>Summary</EM>
174 ----------------------------------------------------------------
175 TRUE FALSE This is the default behavior. <STRONG>ncurses</STRONG>
176 uses operating system calls unless over-
177 ridden by $LINES or $COLUMNS environment
179 TRUE TRUE <STRONG>ncurses</STRONG> updates $LINES and $COLUMNS
180 based on operating system calls.
181 FALSE TRUE <STRONG>ncurses</STRONG> ignores $LINES and $COLUMNS, us-
182 es operating system calls to obtain
184 FALSE FALSE <STRONG>ncurses</STRONG> relies on the terminal database
188 </PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
189 The <STRONG>putwin</STRONG> routine writes all data associated with window (or pad) <EM>win</EM>
190 into the file to which <EM>filep</EM> points. This information can be later re-
191 trieved using the <STRONG>getwin</STRONG> function.
193 The <STRONG>getwin</STRONG> routine reads window related data stored in the file by
194 <STRONG>putwin</STRONG>. The routine then creates and initializes a new window using
195 that data. It returns a pointer to the new window. There are a few
198 <STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure, and its associ-
199 ated character cells. The format differs between the wide-charac-
200 ter (<STRONG>ncursesw</STRONG>) and non-wide (<STRONG>ncurses</STRONG>) libraries. You can transfer
201 data between the two, however.
203 <STRONG>o</STRONG> the retrieved window is always created as a top-level window (or
204 pad), rather than a subwindow.
206 <STRONG>o</STRONG> the window's character cells contain the color pair <EM>value</EM>, but not
207 the actual color <EM>numbers</EM>. If cells in the retrieved window use
208 color pairs which have not been created in the application using
209 <STRONG>init_pair</STRONG>, they will not be colored when the window is refreshed.
212 </PRE><H3><a name="h3-delay_output">delay_output</a></H3><PRE>
213 The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause in output.
214 This routine should not be used extensively because padding characters
215 are used rather than a CPU pause. If no padding character is speci-
216 fied, this uses <STRONG>napms</STRONG> to perform the delay.
219 </PRE><H3><a name="h3-flushinp">flushinp</a></H3><PRE>
220 The <STRONG>flushinp</STRONG> routine throws away any typeahead that has been typed by
221 the user and has not yet been read by the program.
224 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
225 Except for <STRONG>flushinp</STRONG>, routines that return an integer return <STRONG>ERR</STRONG> upon
226 failure and <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>")
227 upon successful completion.
229 Routines that return pointers return <STRONG>NULL</STRONG> on error.
231 X/Open does not define any error conditions. In this implementation
233 <STRONG>flushinp</STRONG>
234 returns an error if the terminal was not initialized.
236 <STRONG>putwin</STRONG>
237 returns an error if the associated <STRONG>fwrite</STRONG> calls return an er-
241 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
243 </PRE><H3><a name="h3-filter">filter</a></H3><PRE>
244 The SVr4 documentation describes the action of <STRONG>filter</STRONG> only in the
245 vaguest terms. The description here is adapted from the XSI Curses
246 standard (which erroneously fails to describe the disabling of <STRONG>cuu</STRONG>).
249 </PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
250 The <STRONG>keyname</STRONG> function may return the names of user-defined string capa-
251 bilities which are defined in the terminfo entry via the <STRONG>-x</STRONG> option of
252 <STRONG>tic</STRONG>. This implementation automatically assigns at run-time keycodes to
253 user-defined strings which begin with "k". The keycodes start at
254 KEY_MAX, but are not guaranteed to be the same value for different runs
255 because user-defined codes are merged from all terminal descriptions
256 which have been loaded. The <STRONG><A HREF="curs_extend.3x.html">use_extended_names(3x)</A></STRONG> function controls
257 whether this data is loaded when the terminal description is read by
261 </PRE><H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
262 The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to <STRONG>ncurses</STRONG>. They
263 were not supported on Version 7, BSD or System V implementations. It
264 is recommended that any code depending on <STRONG>ncurses</STRONG> extensions be condi-
265 tioned using NCURSES_VERSION.
268 </PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
269 The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with portability:
271 <STRONG>o</STRONG> The files written and read by these functions use an implementa-
272 tion-specific format. Although the format is an obvious target for
273 standardization, it has been overlooked.
275 Interestingly enough, according to the copyright dates in Solaris
276 source, the functions (along with <STRONG>scr_init</STRONG>, etc.) originated with
277 the University of California, Berkeley (in 1982) and were later (in
278 1988) incorporated into SVr4. Oddly, there are no such functions
279 in the 4.3BSD curses sources.
281 <STRONG>o</STRONG> Most implementations simply dump the binary <STRONG>WINDOW</STRONG> structure to the
282 file. These include SVr4 curses, NetBSD and PDCurses, as well as
283 older <STRONG>ncurses</STRONG> versions. This implementation (as well as the X/Open
284 variant of Solaris curses, dated 1995) uses textual dumps.
286 The implementations which use binary dumps use block-I/O (the
287 <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use textual dumps use
288 buffered-I/O. A few applications may happen to write extra data in
289 the file using these functions. Doing that can run into problems
290 mixing block- and buffered-I/O. This implementation reduces the
291 problem on writes by flushing the output. However, reading from a
292 file written using mixed schemes may not be successful.
295 </PRE><H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
296 The XSI Curses standard, Issue 4 describes these functions. It states
297 that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but
298 does not define any error conditions. This implementation checks for
301 <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
302 X/Open Curses documented.
304 <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
305 <STRONG>use_legacy_coding</STRONG> has been called with a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG> re-
306 turns the parameter, i.e., a one-character string with the parame-
307 ter as the first character. Otherwise, it returns "~@", "~A",
308 etc., analogous to "^@", "^A", C0 controls.
310 X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
311 initializing curses. This implementation permits that, and returns
312 the "~@", etc., values in that case.
314 <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
317 The strings returned by <STRONG>unctrl</STRONG> in this implementation are determined at
318 compile time, showing C1 controls from the upper-128 codes with a "~"
319 prefix rather than "^". Other implementations have different conven-
320 tions. For example, they may show both sets of control characters with
321 "^", and strip the parameter to 7 bits. Or they may ignore C1 controls
322 and treat all of the upper-128 codes as printable. This implementation
323 uses 8 bits but does not modify the string to reflect locale. The
324 <STRONG>use_legacy_coding</STRONG> function allows the caller to change the output of
325 <STRONG>unctrl</STRONG>.
327 Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
328 of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
329 "meta" keys (codes in the range 128 to 255). Both <STRONG>use_legacy_coding</STRONG>
330 and <STRONG>meta</STRONG> succeed only after curses is initialized. X/Open Curses does
331 not document the treatment of codes 128 to 159. When treating them as
332 "meta" keys (or if <STRONG>keyname</STRONG> is called before initializing curses), this
333 implementation returns strings "M-^@", "M-^A", etc.
335 X/Open Curses documents <STRONG>unctrl</STRONG> as declared in <STRONG><unctrl.h></STRONG>, which <STRONG>ncurses</STRONG>
336 does. However, <STRONG>ncurses</STRONG>' <STRONG><curses.h></STRONG> includes <STRONG><unctrl.h></STRONG>, matching the
337 behavior of SVr4 curses. Other implementations may not do that.
340 </PRE><H3><a name="h3-use_env_use_tioctl">use_env/use_tioctl</a></H3><PRE>
341 If <STRONG>ncurses</STRONG> is configured to provide the sp-functions extension, the
342 state of <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> may be updated before creating each
343 <EM>screen</EM> rather than once only (<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>). This feature of
344 <STRONG>use_env</STRONG> is not provided by other implementation of curses.
347 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
348 <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><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>,
349 <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>, <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>curs_vari-</STRONG>
350 <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>, <STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>.
354 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
358 <li><a href="#h2-NAME">NAME</a></li>
359 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
360 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
362 <li><a href="#h3-unctrl">unctrl</a></li>
363 <li><a href="#h3-keyname_key_name">keyname/key_name</a></li>
364 <li><a href="#h3-filter_nofilter">filter/nofilter</a></li>
365 <li><a href="#h3-use_env">use_env</a></li>
366 <li><a href="#h3-use_tioctl">use_tioctl</a></li>
367 <li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
368 <li><a href="#h3-delay_output">delay_output</a></li>
369 <li><a href="#h3-flushinp">flushinp</a></li>
372 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
373 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
375 <li><a href="#h3-filter">filter</a></li>
376 <li><a href="#h3-keyname">keyname</a></li>
377 <li><a href="#h3-nofilter_use_tioctl">nofilter/use_tioctl</a></li>
378 <li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
379 <li><a href="#h3-unctrl_wunctrl">unctrl/wunctrl</a></li>
380 <li><a href="#h3-use_env_use_tioctl">use_env/use_tioctl</a></li>
383 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>